|Before You Try System Restore|
System Restore should only be used after trying less comprehensive methods of troubleshooting. System Restore changes many files and registry entries, and in some cases might replace more files than you want restored. So when I first run into a computer problem, I reboot my computer. I'm still amazed at how often a problem is solved by using this simple technique. Or, if your computer won't start in normal mode, reboot your computer, press F8 during the boot process, use the arrow keys to highlight Last Known Good Configuration, and then press ENTER.
"If System Restore doesn't work in Normal Mode, it might work in Safe Mode. To use System Restore in Safe Mode, press the F8 key during reboot and choose Safe Mode. When your computer starts in either Safe Mode or Normal Mode, System Restore can be used to capture a working previous state. System Restore can't be opened unless the system is bootable into one of these modes."