Desktop goes into Power Save Mode

Sorry That is Inspiron 560, not Dimension 560.

I have a Dimension 560 with Windows 7. It's just over 6 months old. It recently started going into Power Save Mode and I have no idea why or what to do.  It happens at startup, and when the monitor turns on, the screen is dark with a little blue window that says 'Message. Entering Power Save Mode'  and the monitor goes dark. I can't even go in Safe Mode. I've been reading about problems like this but the messages others get are different, something about moving their mouse or tapping a key, although that didn't work for them either. Any solutions for this please? It's extremely annoying.   Thanks very much

If your system is only 6 months old, then I would give dell support a ring, as it is still in warranty.

The warranty is expired.