i am running WIN7. last week i had some hardware porblem so my comp was unsuccessfully booted several times . finally i fixed the problem. but then i noticed that my Harddisk space was reduced by 3gb. i used all the disk cleaners like DISKMAX and CCLEANER and registry cleaner..but the prob is still there.Can anyone help.....in XP it used to be there the extension .chk i suppose?? please suggest ways to get back that space.