Uninstall it thru the control panel.
Delete: C:\Program Files\PostgreSQL
Then, quoted from PTPat on the PT forums.
Quote:
From the Start menu select Run. Type COMMAND to open a DOS window. Type the following:
net user postgres /delete
and hit ENTER. Then type EXIT to close the DOS window.
When you install, you should only be entering the password, do not change the user name or the domain name.
http://www.pokertracker.com/forum/vi...er=asc&start=0