Cant uninstall and reinstall postgresql 8.4.

I have tried for about 6 hours now to get it working again.

There was a problem with the database and I decided it best to reinstall the program.

Im on W7 64, I used revo uninstaller.

I also manually deleted the user files 'postgres' and postgres files in the program files folder.

i used command promt with 'net user postgres /delete'

when i try to re-install 8.4 i get an error message saying it was unsuccessful.

I then have to uninstall what was installed that time and i tried different versions.

postgres 9.0/9.1/8.39 all had errors installing.

Also i can see after each failed install I get 'postgres.exe' files in process explorer and one of them is using 50% CPU.

there has to be something im missing. If i uninstalled the program surely when its installed again it would not be using 50% CPU, before it was barely using 3%.