BoeingBoy,
Installations of new Operating Systems over older ones, particularly when launched through Windows are easier in the short term, but tend to cause problems later on. Best way always when installing a new OS is to back up all your data files, wipe the HDD clean (format is fastest) and then reinstall from new OS CD, preferable booting from the CD.
Seeing as no problems were found when you scanned the system, I'd suggest going to Windows update. This will look and see if there's any bug fixes you need. To do this simply... :
- Launch Internet Explorer and Connect to the Net
- Tools -> Windows Update
- When loaded. Choose Product Updates
- Get all the Critical updates
- Get all other updates you fancy
If this doesn't work, try uninstalling applications one by one until the system becomes stable. Then reinstall them one by one noting which one kills it. If it doesn't stabilise in the first place, I'd be tempted to formnat and reinstall.
Hope this helps,
Aq