Windows 7 Ultimate SP1 x64 shut down not turn off after updates

I recently installed GTX670 SLI in my machine and run some benchmarks to test it is all working.

Afterwards, I did a clean format complete re-install with Windows 7 Ultimate x64 SP1 with updates. It appears now when I shut down my machine, windows turns off the display and seems to shut down but does NOT turn off the fans/LEDs on my computer.

I then re-installed a clean windows 7, installed my drivers ONLY (no windows updates) and it shuts down/turns the computer off fine.

Not sure what is going on, some update must be causing this? Can anyone help me?

Another install, something strange is happening.

When I shut down. Sometimes it works sometimes it don't.

If it don't then I have to hold power button 10 s and shut down. Then when I turn pc on it turns on for a few sec and then turns off, and then turns on again by itself and proceeds to continue to load up Windows.

Am now reinstalling and going to continue to test this.

I would suggest checking for an application or service conflict first: Troubleshoot Application Conflicts by Performing a Clean Startup.