B5B Deluxe / LAN / driver probs

After upgrading from XP Pro to Windows 7/32, I've been losing internet
access either at startup or sometimes after an hour or so. A restart
or sometimes two usually gets me connected.

I installed the Marvell Miniport driver from the Asus site but still
have the problem. I'm pretty sure it's not a hardware problem as I
haven't changed anything but the OS.

Please forgive me if this topic has been covered. I did search Google
and tried to search posts here but got lost in the tangle of
information.

Thanks very much for any help.

Dave