Hey guys. Sorry to bother you with this but I need your help. Today I restarted my computer and came back to it and it was running a Chkdsk scan and for about a hour it was saying ' Replacing invalid security id with default security id ' for various different files. Now when I log in I can't play any music files, can't copy and paste any files, can't drag any files, the computer won't connect to the internet using wifi. I'm using windows xp, really need your help to get this fixed, I can't see a way ATM. Thanks.