All Games: Sound/Gameplay Issues

I have issues with choppy sound (and choppy gameplay, perhaps as a result?) in Zelda: Majora's Mask (this is true of all my games, even Mario64, though to a lesser extent, but I only really want to play Zelda: MM... my N64 is defective and locks up when I play it on the console, possibly due to the expansion pack). Anyway, I had previously thought that it was due to my older computer. I however just upgraded to a computer four times as fast, with twice as much ram, and I'm still having the same problem, only very slightly improved. The background sounds skip horribly in my games, although sometimes little sounds that don't play continuously are fine. I've tried all manner of plugins and settings, but to no avail. Is there anything anyone can suggest?

Specs:
AMD Athlon XP 1800+ (1.532GHz)
512MB DDRAM
3DForce GeForce2 MMX 64MB 4x AGP Video Card
SoundBlaster Live! Value PCI Sound Card
MSI K7T266 Pro2 Mainboard w/ VIA Chipset
140GB Total Storage (Now I'm just bragging ^_^)
Windows XP Professional

Keep in mind that this runs just as well (read: just as badly) as my old system, with these specs:

Pentium III 650MHz
256MB SDRAM
GeForce2 MMX 64MB 4x AGP Video Card
SoundBlaster Live! Value PCI Sound Card
ABit something-or-other mobo
Windows '98

The sound card is literally the exact same card, being that I simply took it out of my old computer and put it in the new one, but when I switch to my integrated sound (Avance AC'97 Audio for VIA Audio Controller) it doesn't help anything, so I don't think it's the sound card, or, indeed, a hardware problem. So all that's left is software. Anyone have any idea what I could do?

- Orinthe Ducvantol