Jasc Paint Shop Pro Dell Edition repeated installation attempts

I have a Dell Dimension 3100 with Windows XP. Every time it starts up Jasc Paint Shop Pro Dell Edition repeatedly tries to install itself, tells me that it is installing then that it needs a disc, which I don’t have.

I have tried uninstall this program , it refuses then tells me it needs a disc to instal and disappears from the list only to return when I open the list again.

I have uninstalled Corel Paint Shop Pro X as this may be associated to Jasc and have tried to uninstall Corel Photo Album 6. This latter programme refuses to go with the error message:-

“Error 1720. There is a problem with the Windows Installer package. A script required for this install to complete could not be run. Contact your support personnel or package vendor”

followed by:-

“Fatal error during installation”

I have downloaded the latest Windows Installer and followed the procedure suggested by Microsoft in the absence of the Windows Installer Clean Up Utility which they no longer provide as a download because it may adversely affect other programs.

What can I now do to uninstall the offending program(s) and get my computer to start properly?

Thanks