Had the same problem with the 7VAXP today - turns out there is an issue with
the Realtek 8139 going to sleep and not waking up... search
groups.google.com for 7VAXP and NIC...

Anyway, you need to download a program, RSET8139 from Realtek's website, and
then just play around under the Power Management section... it should come
good again.

ftp://152.104.125.40/cn/nic/rtl8139a...et8139-503.zip