Windows xp x64 doesnt shut down

[Iraklis F.C.]

Ok heres a weird problem

Installed xp x64 in a second drive, system is the one in signature. When i select restart/shut down windows seems to finish saving settings then the monitor blinks off and the computer is left running.. I have to hold the power button to turn off the computer. I have tried all BIOS settings, nothing. Installation is clean.

any ideas?

 

[ashrobbo]

Is your bios set to S3 or S1 within power options, or did you install the AHCI driver if there is one?

only thing i can think of.

 

[Iraklis F.C.]

it is set on S3 and i have changed it to S1 with no success. HOWEVER i set APIC to 1.1 from 1.4 and it did worked perfectly for a while until i switched the pc completely off and the same thing again...what does ahci have to do with it?