Help, I have a Dell 420SC that has been working as a proxy server for months, now all the sudden the network will not come up. Says "No interface found" and "failed". When I go into Yast, Network Devices, Network Cards, the first thing that comes up says "No package source defined" with an "Ok" option. Selecting "Ok" then Yast continues on, and "sees" the network cards. I can edit the settings for the cards and everything. What I think is the problem (but don't know what to do about it) is that under the Advanced Settings - Hardware Details, the first card has no module name (onboard NIC, Dell NetXtreme BCM5751), and the second card lists "tulip" as the module name (PCI card, Linksys NC100). When I do a lsmod, there are no modules loaded for the BCM or tulip. I did a whereis on both BCM and tulip, and come up with nothing. I don't know where to go from here. I booted into Knoppix and the cards work fine, so it isn't a hardware issue. I am almost positive that it is the driver issues, but I don't know what would have happened to them. I have deleted the cards from Yast, and put them back in numerous times to no avail. I have even tried using a different PCI card (Intel Pro/100S), and that didn't work either. I am new to Linux and would appreciate any help on this as soon as possible. Thanks in advance for all help.

I don't think whereis will search the directories containing modules (e.g. drivers). The directory /lib/modules contains directories suggesting the kernel name, which in turn contain the modules for that kernel. You can use the find command to look for a module. If you are using the 2.6.9 kernel (I am just making up a number, adjust to your situation) you can for example type (as root):

to search for any module starting with "tulip" (The quotes above are necessary to prevent the shell from interpreting the wildcard.)

I hope this helps.

blackhole54 - Thanks for your reply. I am pretty new to Suse, and that is the only distro that I have any experience with at all, so I appreciate your helping me out with the proper commands.
Where I am at now:
I did the find command from post above, and actually found the files I think I am looking for that are not loading.
/lib/modules/2.6.8-24.24-smp/kernel/drivers/net/tulip/tulip.ko
and
/lib/modules/2.6.8-24.24-smp/kernel/drivers/net/bcm/bcm5700.ko

My question now though is what next? Do I just put bcm5700 under "module name" in the advanced settings for the NIC in Yast? Is there something else that I have to do before that to load the modules? When I run lsmod, neither of them are loaded? Actually, from looking at other posts, there are very few (6 to be exact, raid1, reiserfs, ata_piix, libata, sd_mod, and scsi_mod).
I don't know where to go from here. any additional help would be greatly appreciated.

Unfortunately, I am not familiar with Yast (I've heard of it!) or many of the GUI tools. What you are suggesting sounds plausible to me, so I suggest you try it and see if it works. (Try both with and w/o the ".ko" extension, or rather if one doesn't work, try the other.)

You should also be able to manually load (for example) the bcm5700 module (as root) with the command

Note that this will not cause the module to be automatically loaded on subsequent boots.

If none of this helps and if nobody else posts on how to do it with GUI tools, I can try to help you from the command line, but realize this is not an area I have a great deal of experience with.

Since you indicate you are new to Linux, I don't know if you know about the man pages (short for manual pages). Most CLI commands have a man page explaining how they work that can be accessed by typing (for example):

man modprobe

Some also (or instead) have info pages you access the same way, except replacing man with info.

Good luck.

EDIT: I think most distros have a tool that is automatically run at boot time to detect new hardware. You can try simply deleting the entries for this hardware and reboot and see if it redetects them and straightens things out.