Hello Bru,
It just really depends on how far back you need to go to undo whatever issue you are having before it happened.
You could use step 9 in the tutorial below to see what
drivers and programs would be affected and needed to be reinstalled if you were to finish the system restore. Windows updates that were installed after the date of the restore point would also need to be reinstalled through Windows Updates again.
The contents of your user folders will not be affected though.
System Restore
Hope this helps some,
Shawn