Have been working fine for a while, then suddenly when I clcik on "Make DVD", the program hangs. Put the latest update on, did work (once), but noticed that my dvd writer is not listed. Program now hangs every time I use "make DVD".
It's most likely something outdated in your operating system. (You should be at Vista SP2 and XP SP3 by now. If not, go to the Windows Update site and manually load all of the updates -- even Custom.)
Another important feature is Quicktime, which DVD Architect uses to process video. Make sure you have the latest version.
And, finally, go to the site for your DVD burner's manufacturer and manually download the latest firmware and drivers for your DVD burner. Vista has done a lot of updating in the past several months, and even a brand new computer is probably weeks out of date!
(There is also the possibility that you don't have enough free, defragmented space on your hard drive -- but we don't have enough information to say.)