Restore is not reliable. It's a marketing gimmick for MS.
You can turn it off from Control Panel > System > and then
re-boot and it will purge it's file. Then re-boot, turn it
back on.
You still have to deal the problem, it's a crap program,
that half works, half the time.
Do a real backup and get Erunt for your registry. It puts
a folder on your root dir with a installer.
http://home.t-online.de/home/lars.hederer/erunt/
System Restore In MS's own words .......lol
"The System Restore feature of Windows XP enables you to
restore a PC, in the event of a problem, to a previous
state without losing personal data files. System Restore
actively monitors system file changes to record or store
previous versions before the changes occurred. With System
Restore, you never have to think about taking system
snapshots as it automatically creates easily identifiable
restore points, which allow you to restore the system to a
previous point in time."
"you never have to think about taking system snapshots"
Oh, really.