The current UFT Demo version is stated to be similar to UFT 3.0. Your Demo version may have been different.
If you have suitable backups, you may wish to uninstall all versions of UFT from you computer and then go into the registry and remove any references to UFT Demos that you find there. Then re-boot, reinstall, and hope for the best.
Note: Many of us became familiar with the registry after re-installing UFT 2.7/2.8 on top of defective versions of UFT 3.0 when it first came out. No lasting harm seemed to have been done by this knowledge.