You may be able to restart a system in save mode (Press F8). Now you can carry out a Ceck and repair under resricted conditions. In another article I gave examples to start a Chck/f command on a drive/partition with Start, Execute etc. *Click Start, Run, type cmd, and then click OK. The Command Prompt should appear. Next you need to indicate the disk you want to repair. Type cd C:\ and then press ENTER. If you expect that the error is on a drive other than C:\ substitute the appropriate letter for the drive you want to check. Next, type chkdsk /f and then press ENTER. This command checks the drive you indicated for errors, while the /f switch fixes any errors. You may have to run the utility more than once to fix all errors on all partitions.
With start execute typ MSCONFIG the menu opens and find a previous system restore point
then OK and see if that runs.
If not succesfull you could run repair with your Windows CD