Try pinging the card using the loopback address of and see if the PC gets a response from the card. If that works, try pinging your router. You could also try another network cable. I've had them go bad, especially the ones that I have made - they can get loose on the ends. You should see the activity light on the card working when you plug in the cable so it's either the cable or the network card. I've had the cards go bad too, and usually with no warning where they work one minute and the next they stop, never to work again. They'll show up as okay in Device Manager, but will never show activity. Also, most cards include troubleshooting tools with their software. Sometimes they're on the CD and sometimes they install into the software's directory in the Program Files folder. Their tools may help troubleshoot the issue. Being an older PC, you could also try removing the card and re-seating it. Sometimes they'll creep out of their sockets. I had an old Windows 98 PC that would do that with different cards whenever it was moved.