Two days ago Xp starting asking for a password to log on (even though it is set up to not require a password). I checked and there had been no changes to the accounts. I was able to hit "cntrl-alt-delete" and click "ok" and eventually get in. Beginning yesterday, I have to reboot to gain access - upon reboot the first time I received a message from disk check saying: -- "The size of Documents and Settings\Local Service\ntuser.dat.Log entry is not valid", and: -- "The size of Documents and Settings\Network Service\ntuser.dat.Log entry is not valid" Then after complete scan it tells me problem corrected. However same problem occurs each following time I start up computer, except after reboot I am now always told there is no problem with files; however password popup screen flashes on and off and then goes to "Windows is starting up screen" for about 5 minutes until the log-in screen comes up (Previously took less than a minute to log in). Everything else appears to be working normally, but I would like to eventually be able to turn my computer off again. Any suggestions/help would be appreciated - Thanks in advance for any help.