Try the following and see how you go
System Restore Point facility
Start>All Programs>Accessories>System Tools>System Restore
follow the onscreen directions.
Try to put your system back to a date before your troubles started.
see how you go.
using this facility will normally preserve documents and data created by you in your My Documents folder, but some data files left on the desktop for example are at severe risk of being lost. For this reason it is recommended that before doing anything at all, you check that your back up/archive/copy of all your important data, files, settings, work, etc is 100% up to date accurate and reproducible, (even if your back up is even only a day or so out of date, its worth updating it now.)
Also don't forget to check that you have all your application Installation CD's to hand together with the product keys (including those for Windows itself)
It is always important to have System Restore, protecting your boot drive (usually Drive C:) unless your trusted adviser specifically recommends turning it off for a short while.