firewire failure

vista Home Premium

I have an external high end sound device that runs off the firewire.
(Focusrite Safire). So the internal sound devide is turned off. It works
for a minute or two then sudenly starts spitting out distorted sound. I
has something to do with explorer or what passes for explorer in vista.
If I do nothing else it works fine. If I open another window, ding
around a little... the distortion happens.

I've tried everything focusrite suggested. Also tried closing everything
else, doing boot with no preloads etc. Nothing works.

I am beginning to think it is a hardware problem. It is an hP that came
with vista. I bought Vista and loaded it myself so as not to struggle
with the HP version.

Any suggestions would be appreciated.

As an aside... I was angry to learn that Vista doesn't have a "fixing"
install like XP. What microsoft genius decided that was a good idea?

thanks

john