How old is it? Is it still under any kind of warrantee? Seeing that prices are around $100 now for the system, I wouldn't keep it. As a all in one package, there is a lot that can go wrong, and there is little that is user replaceable. If you are an electronics guru (which I am not, and judging by your question you aren't either
) you could maybe play around with the guts to see what's wrong. It could be a software thing or an electronic component. If hard resetting doesn't work (unplug, etc) I would say it's a lost cause. Sorry.