Computer will not switch off

[(CZ)enda]

My old computer died suddenly. I replaced motherboard, CPU, memory and ATX power source as the old one did not have the 4-pin connector required by the new motherboard and re-installed OS.
The trouble is that when I try to switch the computer off from the XP, I can hear a loud "clank", which is probably HDD switching off, then the computer locks and it must be switched off using a switch on the case. After next restart, it is reported that the PC was not switched off properly (what a surprise ) and then the diagnostic tools are initiated etc.
I have a vague memory I had to resolve this issue on the old computer as well, it had something to do with power management, which is why I cancelled all PM options I could find - no luck.
Any idea is very much welcome.

 

[Trancendental]

Some Mainboards are not compatible with the Windows self shut down.

The PC in my front room does something similar except in turns off the monitor and hard disks then the power button has to be pushed manually.

I can't remember what it is to do with but its either the 'Kernel' or the 'API'?

Have you searched the Microsoft Website?

 

[dave]

http://support.microsoft.com/?kbid=308029