Internet Keeps Disconnecting on One Computer

I curretnly have 4 computers connected to my Network uisng a wireless Netgear Router. 3 computers are hardwaired and the 4th is wirelss. The one in the basement, which is hardwired, frequently loses the internet connection, this is not a problem with the others. Using 20 ft cables, which came with a prvious router, on all 3 computers and the one that is a problem is about 15ft or so from the router. When I ping the router address, I regain the connection. Router firmware is most current version as is the OS and all other software. Using Firefox but same problem with IE. Any help will be appreciated. Thanks

No to both. I do have a wireless card I should try and can switch ports to see if that's it. That's the advantage of this forum, people point out obvious things to try that I'm not bright enough to think of myself.