Is your desktop computer not starting up? Are there no lights or fans coming on when you try to start your desktop computer? If so, here is what to do when your desktop computer does not start.

Dealing with a desktop computer that won't start can be a frustrating experience, especially if you rely on it for work, entertainment, or both. However, before you panic and assume the worst, there are a few things you can do to troubleshoot the issue.

Disconnect external devices

If your desktop computer is not starting up, it could be due to a failed external device connected to it. Disconnect all external devices, including USB drives, external hard drives, and printers. Try booting up your desktop computer again and see if it works.

Check the power connection

Next, you will want to ensure your computer is properly plugged in and that all cables are securely connected. This may sound obvious, but it's a common mistake that can easily be overlooked. Check that the power cable is securely plugged into the computer's power supply and an electrical outlet. Additionally, ensure that your monitor, keyboard, and mouse are all connected properly.

Check the PSU (Power Supply Unit)

If your computer still won't start, the next step is to check for any signs of life. Do you hear any sounds when you press the power button? Can you see any lights on the computer or monitor? If the answer is no to both of these questions, there may be an issue with your power supply.

Now, there are different types of desktop computers: Mid/Full-size Tower, Small Form Factor (SFF), All-In-One, Mini, etc. With the various types of desktop computers come different types of power supplies. Some are external, and some are internal.

External power supplies

Mini, All-In-One, and some SFF computers are actually built on a laptop platform and use external power supplies. Remember that the output from any power supply, internal or external, will gradually diminish to a point where your computer will not start.

And even if you do not turn on and use your Mini, All-In-One, or SFF computer, the power supply is often connected to an AC jack, powered up, and energized. If your external power supply is more than three years old, it is likely time to replace it.

Internal power supplies

All Mid/Full-size Tower and most SFF computers use internal power supplies and use the ATX (Advanced Technology Extended) specification for connectors. Mid/Full-size Tower power supplies are the most common and are readily available at your local computer parts store.

Almost all SFF computers that use internal power supplies are specifically designed (in terms of dimensions, connectors, etc.) for that system. You would have to use the part number on the existing power supply to order another one online.

Note: The following procedures require opening the case of your computer. If you do not feel comfortable taking your desktop computer apart, don't hesitate to contact a local computer repair technician.

Most desktop computer cases are relatively easy to open. Just a screw or two secures the side panel to the case. If you need help determining how to open the case, you may need to find a user manual online. A quick Google search for the make and model of your desktop computer, combined with user manual, should yield a manual. For example: Dell XPS 8950 user manual.

Now, all Mid and Full-size Towers, as well as some SFF computers use power supplies with 20+4 motherboard connectors. You can perform a simple test to check the health of those types of desktop power supplies.

How to tell if your desktop computer power supply has failed

Check for debugging LEDs

If the power supply tests out well, the next step is to check for debugging LEDs. To determine if your motherboard has debugging LEDs, you will need to consult its manual. A quick Google search for the make and model of your desktop computer or motherboard, along with manual, should provide you with a manual. For example: Dell XPS 8950 manual.

The debugging LEDs correspond to the POST (Pre-Operative Self Test) that happens every time you start your computer. The standard four (4) debugging LEDs are CPU (Central Processing Unit), DRAM (Dynamic Random-Access Memory), GPU (Graphics Processor Unit), and Boot drive.

If your motherboard has debugging LEDs, disconnect the power cord from the power supply and then hold down the power button for 30 seconds. Then reconnect the power cord and watch the debugging LEDs for any life. If your computer shuts down when a particular LED lights up, that is the component that needs to be examined.

Reseat the components

If your desktop computer still won't start, try reseating the components, including the GPU, memory, CPU, expansion cards, and M.2 drives. Make sure you disconnect the power cord from your desktop computer and hold down the power button for thirty (30) seconds to discharge any residual electrical current before attempting to reseat any of the components.

In conclusion, if your desktop computer doesn't start, several potential causes should be considered. Following the troubleshooting steps outlined above, you should be able to identify and fix the issue in most cases. However, if you still have problems after trying these steps, it may be time to consult a professional computer repair service.

Whether you are building a new computer or replacing/upgrading your existing one, one of the most important considerations is the Power Supply Unit (PSU). PSUs are vital, as they provide the necessary energy for each component to operate efficiently while ensuring system stability and longevity. Here's a comprehensive guide on how to estimate the power required for your custom-built computer.

Before diving into calculations, it's essential to understand what contributes to a computer's total power consumption. Each component in your build, such as the CPU, GPU, motherboard, RAM, storage devices, and peripheral components, draws a certain amount of power during operation. The total power consumption of the system will influence the size of the PSU you need to purchase.

List your components

Begin by listing all the components you plan to include in your build. The primary components typically consist of:

• Central Processing Unit (CPU): The power requirement varies significantly among different models. Check the manufacturer's specifications (Thermal Design Power (TDP)) for this value.
• Graphic Processing Unit (GPU): This is often the most significant power consumer in a modern gaming PC. Again, manufacturers provide TDP ratings for graphics cards.
• Motherboard: While motherboards consume less power compared to CPUs and GPUs, it's still necessary to account for this.
• Memory (RAM): Each stick typically consumes between 2 and 5 watts of power.
• Storage: SSDs consume less power than HDDs, but still contribute to overall power consumption.
• Cooling systems: Fans and liquid cooling systems also draw power.
• Peripherals: Keyboards, mice, and other peripherals (especially lighting effects) can add to the power requirement.

Use an online PSU calculator

Using an online power supply calculator can simplify the process of estimating your total power needs. Various websites, see links below, offer interactive tools where you can input your components. These calculators take into consideration the specifications you provide and offer estimates based on average power consumption, including some headroom for future upgrades and peak loads.

Now, some online power supply calculators can estimate the power requirements given the specifications of the components. You can use these websites to calculate a rough estimate of the amount of power your computer will require. Here are a few online power supply calculators.

Newegg - Power Supply Calculator

PC builds - Power Supply Calculator

Cooler Master - Power Supply Calculator

Once you have a rough estimate of the power requirements for your components, add some extra headroom to ensure stable and reliable performance. A good rule of thumb is to choose a PSU that can provide at least 20 - 30% more power than your estimated requirements.

Calculate total wattage

If you prefer a manual method, follow these steps to calculate your system's wattage:

1. Find power ratings: Look up the power requirements for each component (generally available on manufacturer websites or retail listings). Write them down.
2. Total up power consumption: Sum the power ratings from each component.
   For example:
   - CPU: 95 watts
   - GPU: 300 watts
   - Motherboard: 75 watts
   - RAM: 16 watts (2 sticks x 8 watts each)
   - Storage: 10 watts (SSD and HDD combined)
   - Cooling: 20 watts (for 4 fans)
   Total power consumption = 95 + 300 + 75 + 16 + 10 + 20 = 516 watts
3. Add overhead: It's essential to add a safety margin to ensure stable performance. It is common practice is to add about 20-30% more power on top of your total wattage. This might look like:
   516 watts x 1.3 = 670.8 watts

Therefore, a 750-watt PSU would be a safe choice.

Consider efficiency ratings

When selecting a PSU, consider the efficiency rating, which indicates how well a power supply converts AC power from the wall outlet into DC power for the computer. PSUs are rated based on efficiency standards, such as the 80 PLUS standard. Here are the tiers:

• 80 PLUS Bronze: 82% efficiency at 20% and 100% load, 85% at 50% load.
• 80 PLUS Silver: 85% efficiency at 20% and 100% load, 88% at 50% load.
• 80 PLUS Gold: 87% efficiency at 20% and 100% load, 90% at 50% load.
• 80 PLUS Platinum: 90% efficiency at 20% and 100% load, 92% at 50% load.
• 80 PLUS Titanium: 90% efficiency at 10% and 100% load, 94% at 20% load.

Selecting a more efficient PSU can allow you to choose a PSU with slightly lower wattage, as it operates more effectively under load.

Plan for future upgrades

If you plan to upgrade your system in the coming years (e.g., adding more storage or upgrading your GPU), consider purchasing a PSU with a higher wattage than what you currently need. This foresight can save you money in the long run.

Estimating the power required for your custom-built computer is vital for ensuring system stability and efficiency. By carefully listing out your components, using online calculators or manual calculations, taking into account efficiency ratings, and planning for future upgrades, you can select the most suitable PSU for your build. A robust and reliable power supply is the backbone of any custom PC, and making the right choice can enhance not just performance, but also the longevity of your components.

There may be a time when your desktop computer does not start. There could be a few reasons why it does not start. The first thing that comes to mind is a failed power supply. Here's how to test your desktop power supply.

Living in Phoenix, we have one thing that takes a toll on a desktop computer. No, it is not the heat; it is the dust. Since our environment here is so dry, we get a lot of dust.

How to clean the dust out of your computer

And since dust conducts electricity, power supplies tend to fail. Even if you routinely clean your desktop computer, it only has a life span of 3 to 5 years. So, if you press the power button, your desktop computer does not start, and there are no lights that light up, you may have a failed power supply. Now, if you do not feel comfortable working around electricity or inside your desktop computer, please contact a local computer technician.

How to test your desktop computer power supply

1. Disconnect the power cord that comes from the outlet to the power supply.
2. After you have disconnected the power cord, open up the case and touch any metal part of the power supply or case to discharge any remaining energy.
3. Make a note or take pictures of the connections that lead from the power supply to the devices. Once you have documented all of the power leads, then remove all of the connectors (SATA, Molex, PCI-e, ATX, ATX12V, etc.) that lead to all of the different devices and motherboard.
4. Create a jumper from a piece of thin gauge wire or paper clip.
5. Using the jumper you created,
   
   connect Pin 16 to either Pin 17 or Pin 18 on the ATX 24-PIN (20+4) connector.
6. Make sure the power supply is turned on and then plug the power cord back into the jack on the back of the power supply. If the power supply fan starts to run, the power supply has an output voltage and is in good condition. If the power supply fan does not spin, it is time to replace it.

If your power supply has failed, make a note of what type and how many connectors your existing power supply has.

Also, check the stated output of your existing power supply from the label on the side.

I also recommend that you use a tape measure or ruler to measure the dimensions of the power supply, (Width x Height x Depth) as you will want to get as close as possible to these for the replacement power supply.