Did you remove dt before removing sptd?
If you did , try downloading the latest sptd from
here and install it if it gives you the option and then uninstall by using the built in uninstall in the exe(when it runs it will ask you) that should remove all the registry entries better then you can manually. If you did not uninstall dt first please uninstall it and then do the aforementioned step. Also did you think about a system restore to just before you installed dt, windows usually automatically creates(don't know about windows 7, don't have it yet) one before the installation of sptd and it is a much faster and easier way if it works.