Cannot Generate System Identifier For General Entity Check System Restore Problem?

System restore problem? - cannot generate system identifier for general entity check

Recently, I authorized my computer a virus and now face a big problem. I need to use System Restore. The fact is that when I use the computer in normal mode, I can not use because the administrator has blocked. I am the administrator on the road. REGEDIT does not work because of "political group" will get an error message for a while. If I restart the computer in Safe Mode, you can actually change the regedit to remove what prevents me from working hard to restore the system's use, but I can not use System Restore when the computer is working in the mode of failure. Now that I've tried to run the file that was stopping System Restore in Safe Mode and then run to delete the computer in normal mode, but that's to generate every time if I did not sign me, so it seemsno way to get rid of it.
Can anyone make a suggestion. I'm using Windows XP Home on the road.
HELP PLEASE!