TRy what 1ginman1 suggested.
To get to the Safe Mode Options Screen start pressing F8 repeatedly when bootup begins.
Try "Last Known Good Configuration"
If that does not work, boot back into the Safe Mode options screen and choose
'Safe mode with command prompt'
At the command prompt type
C:\Windows\system32\restore\rstrui.exe
Hopefully this will open System Restore, so restore to before the problem started
http://bertk.mvps.org/
.