n the Control Panel, click on the System icon and, in the resulting dialog box, click on the Performance tab.
Click on the File System button and the Troubleshooting tab. Look for the Disable System Restore line and put a check in the box to its left by clicking on the box.
Click on Apply, and then immediately click on the same box to get the check mark out. Click on Apply again, then on Close.
Go back into File System and click on the Hard Disk tab. Set the slider next to "System Restore disk space use" to limit the amount of space Windows uses to store Restore Points to 200 to 300 megabytes. Left to its own devices, Windows will hog way too much drive space for this function.