Run disk cleanup - make sure to delete all but the last restore point too. Uninstall all old and unused programs. Use windirstat to locate large files/folders and delete unnecessary ones. After cleanup, run a defrag.
Run disk cleanup - make sure to delete all but the last restore point too. Uninstall all old and unused programs. Use windirstat to locate large files/folders and delete unnecessary ones. After cleanup, run a defrag.
http://windirstat.info/
Ding! Ding! Ding!
CCleaner will find some gunk, too.
edit: Before deleting the old restore points, make sure you have updated all your drivers and OS.