With you computer offline, temporarily disable you antivirus and try to do a System Restore again.
If this doesn't work enable the antivirus and then do the following.
Warning: Disabling items in Services or Startup may leave your anitivius disabled until the process is ended. For this reason I would suggest that you perform this process off line.
(1) Click on the Start orb, then type msconfig.exe in the Search programs and files box.
(2) When msconfig is seen in the pane above the search box and under Programs, right click on it, then click on Run as administrator.
If you are prompted for an administrator password or for confirmation, you should enter the password or provide confirmation.
(1) Click on the General tab.
(2) Click the Selective startup option.
(3) Remove the check mark in the Load startup items check box.
(1) Click on the Services tab.
(2) Place a check mark in the Hide all Microsoft services check box, this will remove the Microsoft Services from the list but will still be running.
(3) Click Disable all, this will remove all of the check marks in the Services list, then click on Apply, then OK. Click on Restart in the window that opens.
When the computer is restarted try doing a System Restore.
When you a finished go back to System Configuration and click on the General, then click on Normal Startup, click on OK, then restart your computer.