I just downloaded MenuetOS and tried to get networking to work with a 3c905b card which should work with the 3c595 driver.
I've setup the driver and the networking stack but I don't seem to get any connection. Also selecting Packet driver reverts the driver to ne2000.
Any help is appreciated.

You need to compile the driver with 3c905 cards PCI identification, otherwise the driver doesn't find the card. You can read the ID from PCI scan applications first column and replace the '595010B7' string at the driver source. The driver is located at /driver/source.zip.

You had better not do it. The driver in M64 does not support newer boomerang (as e.g. 3c905C) cards. As I see it only supports old vortex (as e.g. 3c595) devices. But also for these latter ones you have to change PCI (Vendor/Device) id in the driver source Ville talked about.

3Com cards are relatively professional but quite susceptible instruments. You mess up something in the driver and the card dies. This might also be valid when trying an inappropriate driver (like that of M64).

Yet if you want to try your card under MenuetOs I suggest using any of its 32bit variants (M32, KolibriOs) where the thing should work without any changes.

Endre