Sounds to me that your system has become corrupt. I don't think you have a hardware problem, but may well need to reinstall Windows to get going again. Try loading up Windows in Safe mode first then run SFC (I think that's still live in ME) to see if that resolves anything. If that fails, try reinstalling over the top - this can save quite a biot of effort and amend most corruptions - but not all. If that fails, I'm afraid you will have to re-format C:\ and start from scratch.
If you have any unsaved data on your C:\ drive, make sure you back it up at the first opportunity.