The first thing I would do is remove any discs from the DVD drive. It could be attempting to boot from a disc you have in it. You might also look into the boot order to confirm its trying to boot from the hard drive.
If it is trying to boot Windows from the hard drive but failing you might have a failing hard drive or Windows got messed up somehow and may need to be reloaded.
You might try running a live linux cd
until you can restore your Windows to try to access your data.