I am using XP home on a P4 based system. Your probably right, the IMAPI error is probably unrelated. I'll have to check the number of files scanned at startup when I get home to play with that system.
I haven't tried the msconfig route, but nothing changed in what I was loading from before when the slowdown started. Also, I know that if I disable the standard shield, the boot up speed comes back, so it seems like the problem may have something to do with the number of files scanned at bootup, or perhaps a particular file causing the trouble. I'll check the overall number of files scanned, but is there a way to log the actual files which were scanned, perhaps from that I can narrow down what file/files that may be taking a long time, if it isn't just shear number? Thanks for the quick suggestions.