cackling crackling speakers, gets much worse over time

Hello all,
Another one of the countless problems with Vista I am hoping someone might
have an answer for.

Velocity Micro, 256 MB video card, 4 GB RAM, dual-core 2.66, Vista Ultimate.

Integrated sound. When the computer starts, everything works perfectly
well... well, Vista being essentially a joke,
but when it isn't crashed BSOD, it works fine. I start Adobe Creative Suite
products, typically Photoshop CS2, InDesign CS2,
and also Dreamweaver and Fireworks. All of the exact same stuff I had on a
much less powerful XP Pro machine without so much as a
hiccup in 5 years.

Within about 20 minutes of work, the system gets more and more and more
unstable as time goes along, and Winamp gets more and more
crack'ly and cack'ly as the minutes pass. Just listening to Shoutcast radio
stations.

I have run RAM tests, all come up clean.... I am a very savvy computer user;
it is my livelihood. So constantly cleaned of spyware, adware, defragged,
etc. etc.
all the usual stuff to check. I keep on top of the most recent drivers,
etc. also.

This problem is purely a Vista problem. Vista has been an utter nightmare.

Anyone have any clues why the perfomance takes such a hit as the minutes go
by. I might not even normally recognize that the system is going down hill
except that the speakers start crackling and getting static'y. But sure
enough if I don't restart it, within 15-20 more minutes it will crash to
BSOD.

Tim