Hi all
My cousin has got a PC which I have built for him 3 years ago, it was working fine until last night suddenly it switch itself Off and does not want to power on again. If I disconnect the hard disk the PC works fine without any problem but as soon as connecting the hard disk back again to the PC the machine is died. I thought may be the HD is not longer working, we bought a new HD but still we have the same problem as soon as connecting the new HD the PC don’t work at all.
Any suggestions?
The PC did have window XP on it.

try new cable ,or maybe the ide channel is gone bad on the motherboard ,try take the hard drive ribbon cable plug it into the secondary slot ,usually where the cdrom's are plugged into

I had a similar problem recently, i ended up with a new Mother board and HDD. to verify that this is no your mother board you have to test the hard drive in another pc.

PS if you have any other HDD disconnect them you will also note that if you unplug your mouse or key board you loose power on the PC... this will tell you that the mother board is at fault.

It might not be related to the HDD itself...

Try unplugging every connection in the Computer and put them all back in their correct positions...

In my Computer Engineering class this solution always worked...

The only other thing that keeps popping back into my head is the jumper on the back of the HDD... but its been working fine until recently so it probably isn't that..

Thanks for all the advice i ended up with a new Mother board and HDD as well