Have you recently (since last successful restore) installed any new software or hardware?  If so, that could be the source of the problem, particularly if device drivers are involved.   Do you have any devices which show in device manager as "unknown" or "not working properly" (get to Device Manager via left-clicking on My Computer, select Properties, then Hardware, then DM)?

If you have any other system problems, it may corrupt the system restore points.  Check to see if you have any system error messages listed by doing this:

Go to your Control Panel/Administrative Tools/Event Viewer Check under the System Tab for any listed error messages. If any are found, repost them in a new thread or go to http://www.google.com and input the error message in the search box to see if solution may be listed.

Go into your control panel, click system properties, click system restore, check the box stated to turn off system restore.  Click okay.  Reboot the system.  Go back to system restore, and turn it back on.  Sometimes this works.  But as noted above any system problems you may have can be corrupting the restore points, so you must correct what ever is happening or the new restore points you make will be corrupted as the previous ones.  Kip

no device conflicts or relevant system errors (just DCOM not starting in safe mode and a cdrom block error), but new restore points seem to be working now.  I would try turning sys restore on and off but then I would lose the point I was trying to restore to anyhow, but thanks for the help anyway

Now that SR is working I suggest you do an online scan at Norton.com, run the SFC command and verify your Windows updates are still showing at the MS update site.

thanks again