It took me a few days of scouring Google searches to find the solution to my problem and I’ll just share it here in case anyone ends up in the same predicament.
My precious Daemon Tools (DT) software mysteriously disappeared after an upgrade from Windows Vista Home Premium to Vista Ultimate (the only reason for the upgrade was the need for remote desktop). I figured it was a simple glitch during the upgrade process so I simply went to reinstall it. I was met with an endless loop of installation screens telling me that the computer needed to reboot to continue the installation. Apparently the STPD driver that DT uses was having a problem installing itself. Finally I found the solution! (This only seems to happen when upgrading to Ultimate from a previous Vista version.)
Open the registry by pressing
Windows Key + R then typing
regedit. Once inside the registry editor navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\sptd. Right-click on sptd and choose
Delete. Here you may need to right-click on the folders under sptd, choose
Permissions... and then set all of the users to Full Control. (You’re going to delete them all in a few seconds so it doesn’t matter who has rights to them.)
Reboot and run the DT installer as Administrator (right-click, choose
Run as administrator...). That solved my problem and hopefully it helps you too.