I actually got it to work with the Slipstreamed CD, so it is possible. The problem was that I, stupidly, forgot that XP's Setup program would not recognize my Raid 1 array. I had to provide the Setup Program with the Promise Raid Controller Driver. It then was able to access my C: Drive and find my Windows installation. I was then able to select the Repair option.
While the slipstream CD with SP2 helped, there were nevertheless 64 separate critical updates (not to mention 8 software updates), that needed to be installed. Fortunately, all of them can be installed at once, so you can basically select them all and install. The only dialog box was for IE7. For anyone else, I would recommend installing all critical updates except IE7, then getting that afterward.