Learn
Most Common Mistakes When Building a PC for the First Time
Forgotten power cables, badly seated RAM, and wrong monitor ports.
- Not connecting the CPU's additional power cable (4/8 pin) — different from the main 24-pin connector, easy to forget, causes the PC not to boot at all.
- Forgetting the graphics card's power cable (6/8 pin from the PSU) — without it, the graphics card doesn't work even if correctly seated.
- Installing the heatsink without thermal paste (or with too much/too little) — causes dangerously high temperatures from the very first boot.
- Not applying enough force when inserting RAM — it must click into place on both sides of the slot, "looking" seated isn't enough.
- Connecting the monitor to the wrong port — to the motherboard instead of the dedicated graphics card, a classic we've already covered in detail.
- Not checking compatibility before buying — covered in our dedicated guide.
Tip: before closing the case, turn the PC on with the components outside it (on an antistatic surface) to confirm everything works — it's much easier to fix a problem this way than having to reopen the case afterwards.
Frequently asked questions
Why won't my PC turn on after building it if everything looks correctly connected?
Specifically check the CPU's additional 4/8-pin power cable (different from the main 24-pin connector) — it's the most common oversight that prevents booting entirely.
Is it necessary to test the PC before closing the case?
It's highly recommended — turning on the machine with the components outside the case lets you fix problems easily, instead of having to reopen it after closing it.