If this is a recent problem, use the windows restore point facility to try running with the settings you had a while ago.. It won't always sort it but its the quickest thing to try. Before re-formatting your HDD, try and run the machine in Safe Mode.. if it runs okay then its probably a driver issue. You can uninstall drivers for your sound/network/video etc and re-install latest versions downloadable from the manufacturer website. IF IT DOESN't load them it could be one of the following:-
Faulty RAM (easy to check.. try removing each stick one at a time and seeing if its more stable)
Corrupt HDD. There could just be whats called crosslinked files.. CHKDSK (a free microsoft utility) will normally fix that. There's a DOS version and one built into windows.. Just go into explorer and right click on the icon for your HDD and you will see it there
If all else fails .. do the re-install. The above checks would take only 10-30 mins.. which is the most amount of time i'll ever spend on a customers HDD before wiping it and starting afresh
Hope this helps
computec@talktalk.net
Lee Wainwright
September 2008