Sound Problem

I don't know if this is a hardware or software problem.

My computer is an Acer AMD Quad Core with 8 Gigs memory and 750 GB hard
drive. On board sound (drivers up to date). The OS is Vista Home Premium
X64.

The problem is that the sound plays properly and then suddenly a "garbled
bit" lasting about a second is played and then it plays perfectly for the
rest of the time. CPU usage is under 20% on all cores and memory usage is at
about 24% most of the time. The source of the sound/music doesn't seem to
matter if it is CD, DVD, streaming from the Internet or files on my
computer.

I managed to produce the garbled sound when watching a flash video by
increasing the amount of disk space that Flash could use so, I think that it
is some kind of memory issue but have no idea as to how to solve it.

I am thinking about getting a good sound card and installing that but I
don't know if that will solve the problem or not. I don't even know if I can
disable the onboard sound.

Does anyone have any ideas as to how to solve this?

--
Ron P

Quick questions rarely have quick answers