My guess is that you used the Stash Cleaner in the Expert Zone of RegVac to clean the time zones. This is unchecked by default. If you still have the undo file with those in them, you can restore that undo file in RegVac to get them back.
The time zones are stored in the Registry. If you have a different computer with the time zones in them, you can extract them from that Registry into a reg file and then restore them on your messed up computer.