You can either delete all restore points except the latest one, or all the
restore points.

To delete all restore points except the latest one, use the Disk Cleanup
utility. Click Start, All Programs, Accessories, System Tools, and then Disk
Cleanup. Click on the more options tab and then select Clean up in the
System Restore dialog box.

To delete all the restore points on your computer, disable and re-enable
system restore on the system. Click Start, Control Panel, and then the
System icon. Click on the System Restore tab in the dialog box, select the
Turn off System Restore check box, and click Apply. Clear the check box
again to re-enable System Restore and then click OK.

You can reduce the number of restore points saved by decreasing the total
amount of disk space available to System Restore. Note that less available
disk space will decrease the relative number of restore points.

Launch Disk Cleanup (in the Accessories - System Tools menu) and go to
the More Options tab.  In the System Restore (bottom) section click on
the "Clean up..." button to remove all but the most recent System
Restore point.

Another approach would be to reduce (by half or more) the amount of
disk space allocated to System Restore.  Launch Control Panel - System
and go to the System Restore tab.  Select the hard drive and then
click on the Settings button.  Move the slider to reduce the amount of
disk space allocated then click on Apply and OK to exit.  Reboot the
computer to put the changes into effect.  Warning:  If you reduce the
amount of System Restore disk space too much then the computer may
find that it is unable to create a new restore point if you make a
major change to your Windows configuration or install (or uninstall a
major application program that uses a lot of files in the system
folders.

For more information about System Restore see MVP Bert Kinney's System
Restore pages: http://bertk.mvps.org/index.html

Good luck

Ron Martell     Duncan B.C.    Canada