reinstallation of Posstgresql 8.0 program

I had to remove my Sam Broadcaster program and with it Posstgresql 8.0. During the re-installation, the program stops and gives the message”…could not be installed. Verify you have sufficient privileges…”. I am at the administrator level as a user.

 I have removed the program, all related file folders I could find and ran a program to clean the registry. I have read the FAQ solutions on the web site but apparently I do not understand what it is telling me to do. So, if someone could explain to me what I am missing it would be a great help and please explain it like you were talking to a two year. I might get it.

Shalerman