I had SW hang up on a drawing after installing SP3.0. Quoting from a message from my VAR:
"I did some check and there was some sort of issue with the SP3.0 install (I know, more "Bugs"). That's the bad news... Now for the good news. The fix was very simple. Simple go to add\remove programs and choose SW2004, select change, then repair. Let the system repair the install (with AV off of course). If you could give that a try then let me know the results."
The repair worked. The SP apparently fixed the stacked balloon instability problem.