Built an windows xp machine for mother Inlaw. Has worked fine for two years. Scan for malware and viruses four times a month for her, running avast anti virus. The last week when windows is ldleing and you go to use it. It will ask for a pass word. There was no pass word for this account. So I rebooted and did on line eset scan nothing. Spy bot s&d updated nothing. Antimalwearbytes, nothing. Ran spin right. All ok so I password protected the account. Still the same. Ran cleaner nothing. Ran highjackthis nothing. What am I missing.