|It is best to use the restore option in safe mode.|
I have also found that an anti virus program will also look in the restore folder and remove any found virus's or malware......making the restore point corrupt.
Some times it is wise to make a copy and place in a directory that will not be scanned.
To do this locate and copy.
Click on the "Start" button located on the lower left corner of your desktop.
Double click on the "My Computer" icon in the menu.
Click on the "Tools" option located at the top of the "My Computer" screen.
Select the "Folder Options..." in the drop-down menu.
Click on the "View" tab in the "Folder Options" dialog box.
Remove the check mark by the box labeled "Hide protected operating system files" and check the option box labeled "Show hidden files and folders." This will remove the hidden property option in the System Restore folder.
Double-click on the "My Computer" icon, and then double click the "Local Disk (C:)" drive. You will see the "System Volume Information" directory. Click on this to view its contents.
Double click the "_restore" directory. You can view and find all of the files for the system restore data here.
The above was found some time ago on the net after experiencing the same problem.