PC won't power up or boot

A friend has given me their PC to repair as it ceased powering up.
It has a Gigabyte motherboard. (Running XP)

1st thing I did was to replace the power supply and battery - both with new ones.

When I hit the start button the fans start to spin then stop again - still won't boot.
The light on the mouse and a small light on the m/bd both are lit up.

I had to remove the heat sink to get the old Power supply out - wonder if this caused a problem? Seems to have gone back in correctly.

Any ideas about what may have caused this fault - it may not have been the Power supply or battery of course.

I can't understand why it starts to go then just ceases....
7 answers Last reply
More about power boot
  1. Could you try remounting the CPU heat sink. Also, try booting with only 1 stick of ram and one primary VGA (if Sli). Remove everything else, CD/DVD, HDD's, USB's, etc; Make sure you discharge the motherboard before starting, hold power button in while touching chassis for a few seconds.
  2. If the previous power supply blew out it might have taken the motherboard with it. If what staram5 says doesn't help, perhaps try your friends ram in you computer and see if they still work.
  3. Also, if the "heat sink" you are referring to is the CPU cooler, remember that every time you remove it, you need to clean off the old thermal compound from both the CPU and heat sink and apply a small amount of fresh thermal compound.
  4. Can someone tell me why a poor connection between the CPU & heatsink causes a PC not to power up?
    I'll have to get some thermal grease and replace the old stuff tomorrow when the shops are open - but I just wondered why it stops it powering up at all? I would have thought that maybe it would just run poorly.....
  5. Because the CPU quickly overheats and either fries or shuts itself down to save itself from frying.
  6. How do I clean off the old thermal paste with damaging things? It's dry especially around the edges. Far too much was put on originally and it's squeezed out into the fins! Could that have caused problems... ?
  7. Good instructions are here; you'll be starting at step 2.5: http://www.tomshardware.com/forum/194385-31-part-assembly#t1184072
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