Sure. As it's booting up repeatedly press "F8"
You will soon see a screen with several options.
Choose start in "Safe Mode"
Your computer will let you log in, then will prompt you 2 choices.
Do you want to continue in safe mode or use system restore?
Choose "System restore"
Here is what it will look like.
Select "Restore my computer to an earlier time"
Select a date thats that is prior to your computer going haywire(such as a few days ago)
Click Next and follow the instructions.
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Hopefully this will work. Please let me know.