FWIW, I just ran the 3.3.3 installer last night and left it running for an hour while doing other things. After I returned, the installer was still running--apparently stuck on unopkg.bin. So, using the XP Task Manager, I killed the installer and reran the installer, this time using its repair function. The same occurred. I killed unopkg.bin again and a bit later, a dialog box appeared, indicating that 3.3.3 was finished installing. Version 3.3.3 appears to work, so far.
Somebody should see why the Windows installer does not shut down or finish on its own.
Gary