Computer no longer shuts down correctly

Hi, havent posted for a while on here.

I installed Windows 7 about 2 weeks ago, was running perfectly in about 5 days ago.
It's a pretty slight problem, but it can get a bit annoying.

Whenever i shut down my computer, whether it's from the start menu or i log off and shut down the computer shuts down as normal, but the fans and lights continue to run, and sometimes my external HDD stays running as well. The only way to get the computer to completely turn off from there is to just manually hold down the power button.

I presumed that by logging off first, it meant that it wouldnt be a program that i have running that prevented the shutdown, so it could be a bad install, but then the problem would have presented itself sooner.

Would be nice to see some other peoples opinions on what they think it could be, thanks alot.

Did you change any BIOS settings? Powerdown depends on the APCI settings and the correct HAL loaded in the operating system. It seems unlikely that your HAL changed (unless you reinstalled the OS)...