Have you performed a hard reset by turning it completely off and waiting a couple of minutes then turning it back on?
I am going to post the instructions for a Restore Point but it really seems to be an issue with the monitor. However computers are strange critters at time and sometimes something that doesn't seem like it will work can.
These instructions are from Microsoft. Scroll down to the
If Windows XP does start part then proceed. Just pick a time before the problem appeared. Even if it doesn't solve the issue it is a good thing to know.
http://technet.microsoft.com/en-us/l.../bb457025.aspx