I think my sound card is fuxxed

Oftentimes, when I am running foobar (or any other music player; i've tried a couple) and open something like Firefox or startup FFXI, my speakers start screeching and bring my computer to a horribly laggy halt.

What could the problem possibly be? I'm running Win XP on an Athlon XP 3200 rated at 1.2 GHz (I think, I'm not at home) and a gig of RAM. D: D: D:

any help? ;~;

Why would you play music in FFXI using Foobar (or any other player) anyway? If you don't like FFXI's music, get a file converter, convert the music you want into the file extension that FFXI's music uses, then overwrite them.

Do you use Azureus?

Can you explain the problem a little better?
So you're playing music... then you open PlayOnline and the PC suddenly starts running at about 1fps, with your speakers playing a repeat of the same fraction of a second of music?
If that's not how it happens, ignore me.