If you've been building PCs for a while, you already know it's easy to overlook seemingly unimportant details during the assembly process. For a first-time builder, these mistakes can be the difference between a no-hiccup build and a hunk of junk. If you're unaware of what you could have done wrong, you'll likely assume that your brand-new PC is somehow faulty.

Instead of scrambling to look up RMA information for your new components, take a moment to look a bit deeper into these common rookie mistakes. This might save you hours of trouble and needless panic, and restore your perfectly healthy PC to its rightful state.

6 No power due to loose or missing cables

Ensure all connections are secure

In addition to the fact that there are quite a few cables to connect when building a PC, connecting some cables requires more force than others. These are typically the 24-pin motherboard power, GPU power, and even CPU power cables. If any of these cables are not fully inserted at the PSU or motherboard end, your PC will not receive power to crucial components, and you'll think that something is DOA (dead on arrival).

I once forgot to install the additional EPS power cable for the CPU, and took hours to figure out why the PC wasn't booting up.

Sometimes, a few of the front I/O ports might not work, and you'd wrongly assume that the case is faulty. What might have happened is one of the front USB connectors might have come loose on the motherboard. Other times, you can forget to connect some cables entirely. For instance, I once forgot to install the additional EPS power cable for the CPU, and took hours to figure out why the PC wasn't booting up.

5 Your new SSD needs to be initialized

SSD not detected? Relax, it's not broken

If you've installed a brand-new SSD in your new PC build (instead of using your previous drive), you might be scratching your head when your PC fails to recognize it. This typically happens with secondary storage when you boot into your operating system for the first time and don't see the secondary drive listed on your system.

A simple oversight can easily lead you to believe that your new SSD is faulty and needs a replacement.

If you've installed your SSD correctly, the first thing you should do is initialize your SSD in Disk Management. You simply need to select the partition type (GPT or MBR) and your drive will be formatted and ready to use within seconds. A simple oversight can easily lead you to believe that your new SSD is faulty and needs a replacement. What it needs is just a few hygiene steps that are part of every new PC build.

4 PC not booting due to improperly inserted RAM

The click doesn't mean it's 100% in

This is more common than you might think. Conventional wisdom dictates that you need to align your RAM sticks with the notch on the slot and push them down until you hear the audible click of the latch being secured. However, in many cases, this click isn't a guarantee that your RAM is fully inserted into the slot.

If you can see some of the golden contacts, your RAM might not be making proper contact with the slot, which can easily cause a failed boot.

What you need to ensure is that none of the contacts on your RAM stick are visible. You can look at the DIMMs sideways and inspect them to see whether this is the case. If you can see some of the golden contacts, your RAM might not be making proper contact with the slot, which can easily cause a failed boot. So, before you start panicking about why your brand-new PC isn't turning on, ensure your RAM is fully inserted in the motherboard slot.

3 CPU throttling due to insufficient contact with the cooler

Your cooler installation needs more pressure than you think

Coincidentally, I've been through this ordeal as well. When I was helping my brother build his new gaming PC last year, we faced a strange problem. The PC was booting fine, but the CPU temperature was unusually high even at idle load. We tried optimizing fan curves, but it didn't help. Launching any application (even a browser) caused the PC to turn off instantly.

What must have happened was that we failed to apply enough pressure on the heatsink when installing the cooler the first time, which caused the CPU to throttle.

We considered removing the AIO pump and re-seating it to ensure it was making adequate contact with the processor's IHS. And surely that was the right thinking, as after reinstalling the cooler, the PC stopped shutting down, and temps returned to normal. What must have happened was that we failed to apply enough pressure on the heatsink when installing the cooler the first time, which caused the CPU to throttle.

2 CPU not working due to a missing BIOS update

Your motherboard's BIOS might not be ready out of the box

This is something that has become increasingly common in the last few years. Since motherboard sockets started lasting longer than 1 or 2 years, thanks to AMD, many users have seen their brand-new CPU not work with their new motherboard. This is because manufacturers aren't always able to update every motherboard with the latest BIOS needed to recognize a new CPU generation.

If you've assembled everything and see no signal on your monitor when you turn on the PC, it might just be due to a missing BIOS update.

This means you might end up with a motherboard that has an older BIOS that won't work with your latest processor. Hence, you need to remove your new CPU, install an older processor (which is compatible with the older BIOS), update the motherboard's BIOS, and then install your new CPU on the motherboard again. You can also do this via BIOS flashback, which is an option available on certain motherboards and doesn't require a CPU to be installed for updating the BIOS, simply download the BIOS update from the manufacturer in this case and complete the update.

So, if you've assembled everything and see no signal on your monitor when you turn on the PC, it might just be due to a missing BIOS update.

1 PC using onboard GPU instead of the graphics card

Ensure you disable your onboard GPU

Sometimes, even if you've installed a discrete GPU on your new PC, the system doesn't automatically start using it. In such cases, your PC might work fine, but you'll notice that you aren't getting the graphical performance you should be getting from your graphics card. This is because your applications are running on the onboard graphics by default instead.

To solve this, you need to head into the BIOS and disable the onboard GPU, so that your PC is forced to use the discrete GPU. Each motherboard may have this setting in a different location, but you typically want to look in "Advanced" settings for "Graphics configuration" or something similar.

This will instantly give you the performance you should be getting from your brand-new PC, and assure you that nothing is faulty. In the future, if your graphics card stops working, you might have to reset the BIOS if you want to use the integrated graphics for diagnostic purposes.

Don't jump to conclusions

Building a PC is a learning process. You get better with every build, becoming more confident and comfortable with handling unexpected problems. Hence, as a new builder, don't panic if something doesn't go according to plan; it's all part and parcel of the game. Instead, try to backtrack your steps and see where you could have forgotten something important.

You can get help from other community members on Reddit or XDA forums who have faced the same issue, or consult tutorials from reputed publications. Ending up with DOA hardware isn't impossible, but it also shouldn't be your first assumption.