Click on the advanced recovery methods link.
Click Use a system image you created earlier to recover your computer
When prompted, back up now
After user files have backed up, you will be asked to restart your computer
Click Restart
When asked whether you want the latest system image
Click Select a system image
Select an image from a date before your computer started acting up
click next
If you can format and repartition disks, do so and click next, otherwise just click next
Select all disks if you can repartition, and click OK.
Click Finish.
Click Yes.
Restart your computer when prompted after the restore completes.