win2k n100 error

compaq 5500 server with 1gig ram 4 x 36 gig
nc3120 nic all patch from microsoft are aplied
bios update from compaq and all drivers latest from compaq are on but still get this n100 error network card goes down. i backup files from that server on to another server and it crash with n100 error nothing else shows no other error to help me pin point the trouble