ZIP the entire c:\program files\postgresql\8.2\data folder so you have a backup of all the data files.Use the Start > Settings > Control Panel > Add or Remove Programs window to uninstall PostgreSQL. Uninstalling will still leave the entire c:\program files\postgresql\8.2\data folder intact.
Go to the Start menu and select Run. Type COMMAND on this window to open a DOS window. Type:
net user postgres /delete
into the DOS window and hit ENTER to run it. Type EXIT to close the DOS window.
Download and reinstall PostgreSQL as detailed here:
http://www.pokertracker3.com/products/P ... InstallSQLEXCEPT FOR WHEN YOU GET TO THE WINDOW that has "Initialize database cluster" at the top. UNCHECK THAT BOX and then click the Next button. This will cause it to try to reuse the old ../data folder which has your databases in it.
Once installation completes, restart the computer and try it again.
Hopefully this will work. If it doesn't I'll have to tell you how to send the ZIP file to me with your data folder and I can try to recover your databases for you.