Installation for 15.63

After uninstalling and before attempting to reinstall, I'd suggest deleting the TestComplete branch in the registry.  It might be gone already.

Also, I'd look for anything TestComplete related under: \HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\

The key names are cryptic so you'll have to click on each of them to see the contained data.  As you can see mine is named "{F9706C42-3C24-1500-91B0-B5EA37F86B81}" but yours will almost certainly be different.  If you find anything related to TC delete that key/branch before attempting to reinstall.

Last but not least, you can see the install source folder location identified in the above screen capture.  Delete that folder before attempting to reinstall.

After deleting any of those items restart Windows before attempting to reinstall.

Good luck, John