computer doesn't boot up no POST

[Symetralis]

So , i had a problem with my computer where it powered on then shutted down repeatedly , found out it was an overheating issue so i placed thermal paste on the cpu and everything went fine , i used the pc for like 2 hours to clean up hard drives , then the next morning , i tried to power it on and nothing on the screen , the fans spinned and all seemed to work fine but no boot or post .
searched on the forums and found nothing

sry for my english

hope you can help

[DaveLembke]

First step is remove RAM sticks and reseat RAM. If that doesn't fix it then swap out the power supply or insert only 1 RAM stick and see if that fixes the issue. If power supply swap fixes issue then its the power supply, if RAM stick being alone without other sticks makes it boot then its a memory issue and you need to find out which RAM stick is the cause of the troubles.

If power supply swapped and RAM tested and still no boot then it could be main board related. You can try resetting the BIOS to see if this fixes it. Additionally checking the CMOS battery that it is 3 Volts and no lesser than 3 Volts. If lesser than 3 volts replace the battery and see if it boots then.

If still no boot then it could be an issue with motherboard. Inspect around the CPU and make sure the thermal paste didn't squeeze out and drip onto surface mount components under CPU socket or around CPU to short signals as most thermal pastes are semi conductive due to aluminum in them etc. *Seen before a person load up the thermal paste and apply heatsink and it spread out under clamping pressure of the heatsink and dripped onto motherboard surface and bridged surface mount components causing signals to cross and failed boot. Just a small drop of thermal paste should have been used and not so much that it pours out the sides of the contacted surface of the CPU and heatsink.