Norton 360 and missing pg_twophase, pg_tblspc

Hi there

I've had a serious problem at a client's site where we were called in to
check our app based on postgres that wouldn't start.
After Norton 360 was installed, the source of the problem was located at
the /data directory having two missing sub-directories
/pg_twophase
/pg_tblspc

how could these get removed? is it possible (or likely) for a crashing
postmaster to trash these directories?
Assuming Norton has come down like an anvil on postgres, would it cause
damage to the install like this?
Unfortunately, we can't say it definitely was Norton, because we got
involved in issues there at the eleventh hour.

Any ideas guys? - We have hundreds of users running postgres on windows
servers, if they are going to get fragged like this by Norton ,we need
to warn them all ASAP.

Kevin