computer booted to flashing hyphen. TM restored to xp install, files lost?

computer booted to a flashing hyphen instead of windows after moving it to new office. Time Machine restored to the original xp install with no programs or data.Time machine is set to take snapshot when windows reboots.
Will this destroy any chance of recovering 3 months of information?

Secondly, if I cancel the snapshot, How can I recover my email, documents , etc? I have access to another computer for file transfers.