Sorry--I wasn't really expecting help, as it seems my problem might well be unique to my system, and not worth anyone's effort to fix. However, I appreciate any attempts to do so.
In answer to your questions:
Windows XP Professional Service Pack 3 (build 2600)
Stardock and Luca Saggese - LogonStudio Version 1.00.0064
From Event Log:
Faulting application explorer.exe, version 6.0.2900.5512, faulting module shell32.dll, version 6.0.2900.5512, fault address 0x00032ee6.
Faulting application drwtsn32.exe, version 5.1.2600.0, faulting module dbghelp.dll, version 5.1.2600.5512, fault address 0x0001295d.
I will be away from my PC until the evening (EST) Sunday, Jan 25