I just put an extra 512 stick of kingston memory in my mates pc,with his 256stick,and we had problems so took the 512 stick out now when windows xp has boooted up it comes up windows has found a corrupted file(cant remember the name),run check disk.Ran check disc and it doesnt fix it,any suggestions please,cant access system restore,so is it a format or what,please help.Many thanks.