Probably not. It's most likely that you've got some sort of hardware error
that's keeping Windows from starting properly. In all likelihood your data's
still there.
Whether you keep it or not depends on how you go about repairing things from
this point onward. Your best be would be to take the hard drive out, attach
it to another computer, save all the data you need, then attempt repairs on
your computer. That way, if you accidentally erase everything, at least
you've got your backup.
