That's not it.
If you have a recent backup file then I would suggest you ZIP the current contents of the c:\program files\postgresql\8.2\data folder just to have a backup of this folder and all sub-folders.
Then you should uninstall PostgreSQL using the Start > Settings > Control Panel > Add or Remove Programs window.
Delete the remnants of the c:\program files\postgresql\8.2 folder afterwards.
Then reinstall PostgreSQL from scratch (
http://www.pokertracker.com/products/PT ... InstallSQL )
After that, use the Start > Programs > PostgreSQL 8.2 > Config Files > edit pg_hba.conf option to edit this file and change both places at the bottom where it says "MD5" to say "trust" and save the changes.
Finally, go into PT (you will probably get a db error that the database wasn't found but that's OK) and use the Utilities > PostgreSQL Database Functions window to restore from the last .backup file you have made.
Then you will probably have to close and reopen PT.