How to uninstall “Install Shield”?

Having real difficulties reinstalling Palm Desktop software. It uses Install Shield and immediately terminates with the error:
“An installation support file could not be installed”

I’ve seen comments on other web sites that suggest that it’s Install Shield that’s corrupt. Trouble is, I can’t seem to remove it sufficiently for it to re-install itself.

I’ve looked on the Install Sheild manufacturer’s web site but the few suggestions they’ve made don’t seem to have helped.

Can anyone offer me any suggestions?

Eddie.