Put the 4-in-1's on first. Then patch that Mr.Sid2 mentioned.
Are your SBLive or your video sharing an IRQ with anything else?
You can't manually re-assign IRQ's to PCI cards, you have to assign them to the slots. Normally several slots share with other slots, and onboard devices. Dig out your mainboard manual and it should have the details. Generally the first PCI slot beneath the AGP slot shares with the AGP. The second PCI is often a good choice. Third PCI sometimes shares with USB. If you have a second IDE controller on the board (RAID or anything like that) it will share with other slots as well. It's not usually a matter of changing what IRQ's are in what slots, but moving the soundcard to a slot that isn't sharing with anything else.
Bloody creative drivers SUCK. Does msconfig work in XP? If so, try un-checking config.sys and autoexec.bat so they don't run, XP doesn't need them. Just doublecheck that everything works OK. That's what I do, because the SB drivers will just write themselves back into the files if you REM them out. I just don't run the autoexec.bat or config.sys instead, they are only for compatibility, and are not required by the OS.
Run the 21.81 Detonators... trust me.
http://www.otakupc.com/downloads/nvidia_drivers.shtml