This info on answers.microsoft.com might be useful to fix it.
Also I found this on Windows Support KB947215 ClickHere
"Occasionally, Windows might not read your user profile correctly, such as if your antivirus software is scanning your computer while you try to log on. Before you follow the methods here, try restarting your computer and logging on with your user account again to resolve the issue. If you restart your computer and it does not resolve this issue, use the following methods to resolve this issue"