my PC is dead

[V10R37]

I turn it on, HDD light blinks only a few times at the beginning, mouse, keyboard and display do not work.

[Artem]

Try someone else's video card in your pc and see if that changes anything.

[Aleks]

hmm...I wouldn't say your whole PC is dead. May be the motherboard or a critical component like that. Try testing each component individually to find the issue.

[SAV1OUR]

I turn it on, HDD light blinks only a few times at the beginning, mouse, keyboard and display do not work.

are all the psu cables connected? 

[xToFxREAPER]

I turn it on, HDD light blinks only a few times at the beginning, mouse, keyboard and display do not work.

Test gpu in other pice slots, unplug and re plug usb devices such as keyboard and mouse after the system is on. Test gpu in another system if you can get your hands on one. Try a cmos reset as well sometimes weird things like that can fix the simplest of things

[XionEternum]

@V10R37 Step one: Check POST LED display on the motherboard during boot. If there isn't one, proceed to step two. If there is, check the POST code it hangs on with your motherboard's manual. If the PC is a retail model and not DIY, then consult with the manufacturer on the POST code it hangs on.
Step two: Remove all RAM DIMMs and organize them into a single-file line. Place one DIMM in slot A1 and test boot. If it fails, rinse and repeat with each DIMM. If none allow boot, proceed to step three.

Step three: Disconnect power completely, and remove the motherboard battery. Press and hold the power button for 5 seconds and replace the battery after another 25. Reconnect power and test boot with RAM in it's normal configuration. If it fails to POST again, odds are you have a corrupt BIOS and need to either acquire a replacement BIOS chip from the manufacturer or eBay. If it's a recent ASUS motherboard, use their USB BIOS flashback utility.

[V10R37]

@V10R37 Step one: Check POST LED display on the motherboard during boot. If there isn't one, proceed to step two. If there is, check the POST code it hangs on with your motherboard's manual. If the PC is a retail model and not DIY, then consult with the manufacturer on the POST code it hangs on.

Step two: Remove all RAM DIMMs and organize them into a single-file line. Place one DIMM in slot A1 and test boot. If it fails, rinse and repeat with each DIMM. If none allow boot, proceed to step three.

Step three: Disconnect power completely, and remove the motherboard battery. Press and hold the power button for 5 seconds and replace the battery after another 25. Reconnect power and test boot with RAM in it's normal configuration. If it fails to POST again, odds are you have a corrupt BIOS and need to either acquire a replacement BIOS chip from the manufacturer or eBay. If it's a recent ASUS motherboard, use their USB BIOS flashback utility.

No post LED. Network lights at the back are no longer on. Permanently on before. I will try to check all 2X2 GB of RAM. I don't know how to do step 3 after unplugging my PC.

[XionEternum]

No post LED. Network lights at the back are no longer on. Permanently on before. I will try to check all 2X2 GB of RAM. I don't know how to do step 3 after unplugging my PC.

@V10R37 You will have to look for a small silver disk about the size of a nickel. That's the motherboard battery. It'll have a small latch (that is also one of the leads for the battery, but not part of the point), you can use a small thin screwdriver to pop it out if you can't get your fingers/nails to do it.

[V10R37]

Back on my PC, now with only 2 GB of RAM. The RAM is good, one of the slots on the MoBo is not working.

 

EDIT:

After using it for some time with only 2 GB I tried the other slot again, now it works.

I'm back to 3.5 GB usable.