<<...I cannot run a repair install because I am running SP3, and the disk is SP2 I believe.>>
Well...have you tried it?
I just did one, earlier this morning. Had a number of issues develop which I incorrectly read as something other than memory problems (spent all day yesterday trying to deal with those). After I finally realized that it was a memory problem (and a CMOS battery situation), I was able to do a repair install of my (previously) SP3 system, using a SP2 CD.
It worked...repair was made...reinstalled SP3 from WinUpdate less than an hour ago.
I also had IE 7 installed previously, which reverted back to IE 6...with no visible problems.
The one anomaly of the repair seems to have been the creation of a new user, with some of my desktop, favorites, etc. missing. But I looked in Docs & Settings and found all of them neatly bundled under the former identity I had assumed when installing XP previously. This probably was caused by failed efforts yesterday to properly diagnose what was wrong
If you do decide to try it, I encourage you to have backed up any files which you consider essential.