*Sees XP* HMM. This sounds AWFULLY fishy now.
I just finished making a brand new old XP computer on the weekend; did all the patching. I never saw a Live installation update...
You're absolutely sure it was the official Microsoft site; correct? Because I'll check on my own comp, but you'd think I would've seen the upgrade the other day if it was a real one...
And especially with this safe mode booting problem, and... You say it's slow? Hmm. However, I don't want to be harsh, but it is possible that slowness can be related to the hard drive being on it's last legs... Mostly from experience, given I've gone through at least two of them. =P(One which out and out crashed... Lost everything then. >_^ Luckily it was back in like '03, so I didn't lose that much. =P)
However, after that guy comes to check on the computer, unless he has some bright idea of what to do, I'd follow MTM's instructions. And maybe look into the possibility of a new AV program. =P
Yes, it was Microsoft.. left hand side of the page Optional updates.