|Then it may be best to backup your personal data and then perform a factory restore. |
In the future I recommend that you not install hardware drivers from the Microsoft update site. Not sure if that is what you did this time or not, but I suspect you may have.
If you want to play with things a little more prior to restoring then you could remove the updates you downloaded recently. They can be found in the add/remove programs section of Control Panel. Be sure to check to show updates. They should show the date they were installed.