Well, it's pretty easy actually. Click Start, then Go to All Programs. Then go to Accessories, then system tools, then finally system restore.
To create a system restore point, click the little button that says "Create a restore point" and click Next. Then, type in what you want to name this restore point, and click Create. Wait a few seconds. Eventually red lettering will come up stating that you have created a system restore point for whatever date you have on your system clock.
To go back to an earlier point, navigate back to system restore through the start menu. When the wizard pops up again, click the button that says "Restore my computer to an earlier time" next to it, and click next. This should bring you to a calendar of sorts. Days that have system restore points have bolded numbers. Be sure to restore to a recent restore point, and not one from way back. Going back to a restore point usually recovers missing drivers and the such, and will go back to before you had problems. Anyways, click the restore point you want to go back to, and then click next. This should bring you to a little write-up on what the system restore won't do and what precautions you should take. Click next again, and let your computer restart. Once you restart and you log on, it should say it successfully restored to an earlier point.
I hope I helped!