My computer does not turn on at all

This is a common problem when the issue involves the motherboard or the power supply unit. There are a couple of steps you can take to find and solve the problem.

First and foremost clear the CMOS by removing the battery for 15 seconds. Sometimes you have to reset the BIOS and clear some errors to be able to fire up your PC again.  

Make sure all connections to the desktop are secure. This includes the power cable, 24 pin motherboard cable, and the CPU cable. All the plugs and cables must be properly plugged in.

Check the small switch at the back of your power supply is on. Most of the time people forget to turn this switch on after assembling the PC. 

There are cases when the front panel connectors may get loose – check if they are properly connected. Unplug and plug again the power and reset connectors. 

Unplug the power cable from the wall or try a different one. 

Finally test your PSU. Testing the supply is not as easy as it sounds. You can use this method but be extra careful. 

At this point if the PC is still silent, we may assume that the PSU or motherboard is dead. If you have another PSU, swap and test again.

Motherboard issues, however, are not so easy to diagnose and the best approach in this case is to RMA the board or to use a specialized repair shop to pinpoint the problem.