NIC driver

I have a win95 machine with a 3com nic in it.The computer went off the network yesyerday and upon investigation the 3com nic appears in the device list with an exclamation mark beside it.It appears that the drivers are gone.So I reinstalled the drivers and it works fine until the computer is shut down and restarted and it goes back to the way it was with missing drivers.
Can anyone help me with this problem.

Regards
Damian