BSD: a pattern

I'm really reluctant to reinstall my Win2K SP3 system, which
has been well behaved for two years now. However, over the
last five months, there has appeared a BSD situation I can't
get to the bottom of.

It occurs only when I'm on line (a DSL, but one which
requires me to enter each time I boot). I'll get some time
on line, ranging from 15 minutes to several hours, but
unless I disconnect the DSL, the machine will eventually
crash.

The blue screen produces the following:

"STOP: <...apparently addresses...>
DRIVER_IRQL_NOT_LESS_OR_EQUAL
Address...<hex address>...base at...<hex address>
Date Stamp 3d2b4434 - mrxsmb.sys
If you have not seen, etc... "

A cold boot is required.

I've reinstalled the DSL app, the latest video driver
(Radeon 7500), and removed startup items one at a time, all
to no avail. I've tried Netscape 4.7 and 7.1 and IE 5. I've
rebooted in debug mode and booted into safe mode, but don't
know what to do there. All installed programs work well and
quickly.

I'm not an OS mavin, just a long-time user, so I'm probably
overlooking something obvious (this is my first Win2K
installation). Perhaps you all might have a suggestion or
two. I'd be obliged.

Bob Bollini