Pilko said:
The keyboard lights don't come on no. Would that suggest that the problem is actually the motherboard? Shall I replace it with another that is working and see if that works? Is it ok to keep swapping cpu and everything over all the time?
No keyboard light flash means that the system isn't getting very far through the POST test. In fact, it suggests that its not even getting as far as checking the RAM.
Check the PSU (or try a different one) because although the psu comes on, if its not supplying enough voltage to the mobo, the system won't boot.
If psu checks out then you could well have a duff motherboard or CPU.
Before giving up on it completely though, try the following :
Make sure that :
1. the mobo is out of the case. (place it on a sheet of plain, non-coated cardboard or wood, not paper, to avoid shorting anything)
2. unplug all front panel connectors from mobo except the soft power one. If it doesn't reach, then you can turn system on by briefly bridging the 2 pins with a screwdriver.
3. disconnect everything except RAM, video, cpu, keyboard & psu.
4. Clear the cmos for about a minute & reset it.
Try to boot system.
If you still don't have any luck, then I would suspect the CPU or mobo as you said the RAM & video are OK.
Be careful if you do swap the cpu about - if heatsink is removed at any point, you should renew the thermal compound before powering it up again.