Com+ broken

I got SP2 installed (in safe mode after lots of tries)
successfully, only to find a long wait at the welcome
screen and some constant error in line 44 of com+. The
only effect i've seen so far (other than the slow boot)
is that McAfee VirusScan keeps getting disabled because
it doesn't register with DCOM within the required
timeout. Event viewer suggests tht I reinstall the com+
system and/or inform Microsoft product support.

I view anti-virus as improtant and would like to fix it
(already spent a day fully removing it and re-installing,
wish McAfee could come up with an uninstall that worked,
though it is better than Norton)

suggestions appreciated. (This is an XP Home system, so
lots of the useful troubleshooting options aren't
available)