MN-710 Drops connection

I have a Microsoft MN-710 that drops connection.
I can be using Internet Explorer with no problem at all.
It's when I start downloading files in the news groups that
it suddenly dropps connection.

I've tested this using a Dlink DI-524 router and a Linksys BEFW11S4
with windows 98se and windows xp on the same machine with seperate
installations (not duel-boot)

My system consists of:
256MB DDR Memory, 900 MHz AMD Athlon Thunderbird processor
on a Gigabyte GA-7VTXE+ Motherboard.
with VIA KT266A / VIA VT8233A chipset.

I just added a USB 2.0 Card thinking this might help,
but there is no change.

Anyone have any ideas that might help?

HM