Can installing Windows updates slow down your computer??
With certain computers, SP2 has proven to slow down machines, especially older ones. (2 years or more).
They (MS) has a 10% (guess) problem rate.
I never loaded SP2, I just keep updating XP-with SP1.
It may also slow down whilst you are downloading,but should go back to normal after d/load is finished
I heard a guy's wife left him after he installed sp2...
I have not noticed any change at all. In fact my benchmarks haven't altered one iota since sp2 with all driver updates.
There are some issues with conflicts with certain setups, and some spyware will cause your firewall (if you enable it, recommended) to make your machine misbehave in weird ways.
If you're having probs, I would suggest unloading all known & suspected "adware", and trying again. SP2 is way too useful to not install it because of adware conflicts...