nothing works help

ok about a week ago my computer turned itself on when i was in bed
then about 10mins later switched itself off

i got out of bed went to turn my computer on and nothing happened
so i spoke to someone and he said it was the motherboard
so i bought a new motherboard and ram, it still didnt work
so i bought a new power supply
great it turned on but nothing loaded up
i got told the processor was too old for the new motherboard (1.2ghz amd) so i thought id use my old motherboard
so i put it back together and switched it on
it powered up but there was no beep a few seconds after you switch it onlike there was normally and the monitor never came on :S
i tried another much odler hard drive and nothing happened with that

im lost at what to do
my only thought was the IDE thing on the motherboard wasnt working so i tried putting it in the 1 for the CD rom which never worked either

Sounds like your moniter isn't connected/faulty

This must be getting expensive

my monitor is came on when i tried it with the other motherboard and ram
it just wouldnt load windows

i tried a new monitor last night and it still didnt work
any other ideas

OK, just to get this straight ...

You are trying to load windows using a new motherboard, processor, and ram, it posts, but will not load windows (which version?) ...

Have you tried loading in safe mode and removing the old motherboad drivers from the device manager? (Press F8 repeatedly during/after post to get menu, then chose safe mode, right click my computer, click properties, sleect device manager tab, or if windows xp, hardware, then click device manager).

The alternative is to do a full re-install.

i cant do anything
i switch the computer on
you can hear the power and the CD rm lights up
but theres no beep like there normally is and the monitor doesnt come on like it used to so i cant select safe mode or anything like that
but ive tried a new hard drive motherboard power supply and graphics card

Sounds like a ghost to me...