Hi Alice,
Do you mean that your Windows is not starting up to your desktop?
Try this:
Restart your computer in 'Safe Mode with Networking Support'.
(To do this: Power on your computer and start tapping the F8 key at the top of your keyboard rapidly until the Windows Start Menu appears. Then select the Safe Mode with Networking Support menu option and press the Enter key)
Let me know if you can successfully get into Windows this way.