I was mucking around in my computer (like I always do) trying to install a network card for
a home network. Anyway, in te process, I did something that cut all sound. The sound card isn't showing up in the device manager, and when I re-install it, the comp won't recognize it, (likewise the network card). I suspect something is disabled in the BIOS set-up, but I've reviewed it carefully and don't see anything wrong. Usually when you install a card etc. the computer tells you it's found new hardware, then you install the drivers etc.

Try changing the PCI slots, usually the computer will recognize the relocation and a new device and prompt you to install it.

Tell us about your computer.
Make & Model??
Motherboard if you have a home built computer??
Soundcard??
NIC card??
Operating System??

Sorry about that River Rat, here are the gory details: It is a home-built comp, it's got a Biostar mobo M7VIT 800 (socket A) with an AMD Atyhlon XP2700 256kb chip. A Chaintech SA5500T2 256mb 4X/8X AGP card, a Soundblaster 24 bit soundcard (I'm not a big super sound guy) a Hitachi 60GB/7200/2mb/ATA-100 hard drive. I also put a Linksys 10/100 Ethernet network card in it (which is another thing the comp won't recognize) Anyway I did switch PCI slots for both cards but no luck. Things were fine until I started fooling around with this networking stuff, but the fact that the comp won't recognize componets is strange. I always make sure the cards "seat" well so thats not the problem.

Is there any reason you are not using the integrated Sound & LAN on this MB??

Enter the BIOS and make sure PnP is Enabled.
Have you been to the Device Manager and Right Click the Sound Devices & LAN card and Removed or Deleted them and restart to see if the OS will see them and try to install the drivers??