Computer won't switch off

[revorocks]

Well many people may be having problems with there computers not turning on, well mines different...It wont turn off.

Basically i click on shutdown and it starts to shutdown and then you here the harddrives turn off but then the fans are still going and the screen still says windows is shutting down. i know its definatly not the psu or the os because i have just formatted it and reinstalled yet it still does it.

What could it be and how can i fix this?:confused:

Thanks.

Ps. This is a different pc to the one im using now.

[primesuspect]

just out of curiousity:

If you boot the computer up in safe mode, and then try to shut it down - does it shut down?

[revorocks]

Well, i honestly dont know because i cant get it too boot into safe mode.

Its F8 right?
or is it F12?

ive tried both and it doesnt boot into safe mode.

[mmonnin]

Its F8. When are you pressing F8?

[RyderOCZ]

Give us the details of the PC, what mobo, etc.

Why do you say its not the PSU?

Is ACPI enabled in the bios?

[revorocks]

Well, i just managed to get it too boot into safe mode and nope it still doesnt turn off. As for ACPI it says in the bios

ACPI Suspend Type (and it was set on) S3(STR)

There are also 2 more options

S1(POS)
S1 & S3 .

Also about the psu, i know it isnt the psu because i have changedf it twice yet it continues to do it.

As for the Motherboard i have no idea... doesnt say on the case, doesnt say on pc info software... all i know is that the pc is a Phillips Freeline MT1200. pentuim 4

Also lucky me... another problem has begun. The sound doesn't work. its not the sound drivers, and all the connections are fine. its only been happening since i switched over to a new case but that still should affect it... could i of damaged it?

i have no idea where all those small connectors go for power led and front usb... The front usb and power reset and button works.