my girlfriend has a laptop with XP home installed , its got very messed up and corrupted , she has somehow managed to wreck system restore , and deleated heaven knows how many system files . there are no backups , and nothing works right any more . worst still is , that she has not got an installation disk . or restore disk . what i would like to know is , can i use my own intallation disk to repair her system , bearing in mind that the product key would be different , I dont want to compromise windows update etc. any help would be appreciated.