computer works fine until I install SB Live 5.1

Okay computer guru's hoping someone will know the answer to this.
Got the A7V266E and 1800 XP running fine.. installed everything.. running XP on it.. Disabled onboard sound. Turned off computer.. opened up case, installed SB card in slot 3 turned on computer and it wouldn't boot. Wouldn't even get a video signal (got the rainbow effects on the monitor).
Put it in slot 4 and same thing. Unplugged the sound blaster card. Turned the computer back on and it boots fine. What could be causing this problem? I am so frusterated over this darn computer I could throw it out.
Everything worked fine with the 1 gig athlon on the Abit board.. as soon as I move to the XP processor... I wind up having to get a new mobo, new ram, then new video card (thought the old one was bad), new power supply, now it looks like a new sound card is in order. Might as well have bought a brand new computer.

So... is the sound card bad or does it have something to do with settings?