Recovering .PST file with 0 Bytes

Hello,

Yesterday one of our users lost their .PST file. It seems that the user was having a problem with their system, so we wiped HD -> copied .PST file back with fresh XP PRO with SP 1 with all critical updates. From there the user started using Exchange no problem. The next day the .PST file was missing, we recovered a .PST file with Rundelete but it has 0 bytes… what now?

Tx

Toby