Hello Big Geoff and welcome to the BC Hijackthis forum. Stopping an installation during execution can cause all kinds of problems. Only various parts of the application gets installed and not the entire application so you usually end up with numerous error messages.
About the only thing I can recommend for you to do is go back and do a complete installation. After that is done you can uninstall it through its uninstall option.
If you need assistance with that, since it's not related to malware, the Windows XP Home and Professional
forum should be able to help