hei again

a few week ago i installed a computer for my friend with server specification (~US$ 1300) i installed with RedHat 7.3 (this is my favorite one distro release), the intel board have two NIC, first PRO/100 and second is PRO/1000, this board have RAID card intgrated (i am using Mirrored / RAID 1) the installation took the driver for the SCSI card (no problem i think) but why only one NIC detected, after the installation process finished i switched to RedHat 8.0 the PRO/1000 is detected!

how to insert the driver for my second nic
#insmod ?
#or i have to rebuild the kernel again

thanks