This has happened to me also. Check that you do not have "MS Software Shadow Copy Provider" disabled as it affects the Restore Function. Go to Start-Control Panel-Administrative Tools-Services and scroll down to "MS Software Shadow Copy Provider". Click on it (one click to highlight it) then go up to the left side where you will see "Start Services" and click on that.
Check your settings under System Restore to see if you have it set to the maximum amount of disk space. Click on Start-all programs-Accessories-System Tools-System Restore. On the left side you will see "system restore settings", click on that and check that you have the disk space usage set to maximum. Also make sure that the box marked "turn off system restore" is not checked.
I would then create a system restore date and check to see if it works.
Check your settings under System Restore to see if you have it set to the maximum amount of disk space. Click on Start-all programs-Accessories-System Tools-System Restore. On the left side you will see "system restore settings", click on that and check that you have the disk space usage set to maximum. Also make sure that the box marked "turn off system restore" is not checked.
I would then create a system restore date and check to see if it works.