Solved: What's wrong with my monitor?

Howdy, folks. Please help...

I came home today to find that my monitor, once booted up, displays the message 'Input not supported'.If I restart I can successfully boot up in safe mode, but not normally. It's an Acer v223w. Before this happened I had used TeamViewer to change my computer's resolution remotely, if that's relevant. Running Windows 7.

Can anyone help?