• Download and run the installer, courtesy of rich2323.
• Everything just works, yeah!!

OPTION B

• Download the A&T Sanctum zip file
• Pick a clean install location (INSTDIR), like D:\Games, open the zip and drag/extract contents to there
• On Win7 and Vista, check to be sure the Properties->Compatibility->Compatibility mode is set to "Windows XP (Service Pack 2)". Do this by navigating to your INSTDIR\bin, right-clicking on the Sanctum.exe, choosing "Properties" and the compatibility item. Also do this to the Sanctum-Debug-2008.exe.
• Run Sanctum.exe and it will prompt you to show it where the top level install directory is, so browse to your INSTDIR, the one that contains the bin\ directory, and select one of the Release Notes.htm files and it will start and set the install directory in the registry.
• Send email if you have any problems.

Notes:

This client is NOT dependent on any of the previous Sanctum installs, so you can try installing just this on any machine and it should work. Also you don't have to worry about having any other Sanctum install on your machine, you can run old and new, as long as you don't drop these files into the same install directory of a previous Sanctum. You will only be able to play games against other players using this client. Also, if you want your old decks you will have to manually copy them from your current Sanctum install Decks directory to the INSTDIR\Decks of this install. The Debug version will be slow, but if you're finding bugs it will log them better.