System Sluggish

I have an AMD 500 with 512 Megs ram and a 32 Meg 3dfx Video card and for some reason, I constantly get a MAJOR slug in the system. Example: I am listening to MP3’s with Ultraplayer and I open say Dreamweaver or Paintshop and within a few seconds, the music sounds like it is stopping and restarting, it flutters, and my mouse seemd to get REALLY SLUGISH… How can I fix this annoying problem?