Windows restore is a wonderful utility for the protection of your windows.whenever you install fresh windows with all your required softwares.(Please check if every software is working fine) , you can create a restore point for that date.Name that restore point with a little description. so that you can recall it later.windows will make a small registry backup for that date.(you can also create a restore point every week , or after every two weeks , depending on your work load and installations.)
Whenever you feel like that your windows registry is corrupt OR installed software are giving errors , OR you feel your system is getting slower , due to virus activities etc. Now its the time to restore your computer to an earlier date when every thing was working very fine.