Windows 7 freezes

Windows 7 used to freeze after a random time. I tried to find where the problem came from and saw that when one the the services, namely power, was desactivated, everything goes fine, except for one thing: now I don't have any sound any more! I thought the freeze problem had something to do with the MB temperatures and checked that with nothing wrong there. It should not be a problem with the devices or the drivers, but with Windows 7 that has been updated. I guess it could work with the service constantly disabled, but I need the sound.I hope someone can help me out, so lots of thanks for any hint.
Basic information: I have Windows 7 ultimate, a NVidia graphic card, a 500W power unit.

It's nearly always driver related, in my experience, when you get freeze-ups like that. Have a look in Control Panel>Administrative Tools>Event Viewer, and see if anything in there sheds any light on what might be causing the freeze-ups. If you don't find anything there, then I'd advise a clean reinstall of Windows. If the freeze-ups stop after that then you know it was a software or driver problem. Then the thing to do is to reinstall software slowly over a period, I never install more than one app in a 24 hour period, so that I can see what, if anything, causes problems.

If it still continues to freeze after a reinstall than at least you know for certain that it is hardware related.

OK, I will try a new clean install. So far I just want to send my thanks to the the ones who gave me some hints. I may have to ask for help later, so I hope they will be still there in that case. It is good to know there are people you can rely on. Have a nice day!:)

Andre--Concerning the freeze, if that is still an existing or possible future problem, try Internet Explorer|Tools|Internet Options|Advanced tab|Reset (near the bottom right).
There is a downside from this, but the results could be quite positive.
http://support.microsoft.com/kb/923737

Hi, I'm back again. Didn't want to leace without saying many thanks for the last reply too. Yes, I noticed some problems with IE of the kind Microsoft mentions there. Anyway, I did a clean install before reading your post, Welshjim, now everything is fine again, but it might have saved me the trouble. Greets!