I know some of you guys are network whizzes. Please take a look at the above ^ link and see if you can't help me out. I would really like to avoid returning my router...
Ok, first, enter the router config, goto the DHCP tab and make sure the DHCP range is set to more than 2 numbers
(for linksys usually 192.168.0.xxx to 192.168.0.yyy if i member right.)
If its not, then by jolly, increase the range.
Second, check the mac filtering to make sure, for whatever reason, the third computers MAC address is not blocked.
(Unless someone SPECIFIACLLY placed a mac address in to be blocked, it should be blank. NOTE: this is not the same as the "MAC address" tab, that is used to set a mac address for the router itself. I belive the section you want is on the filters tab.)
Third, you know how to use/run ipconfig /all, ipconfig /release and ipconfig /renew?
If not, after verifiying the points above, hook the third machine back up to the router, boot up, and run in this oder from a CMD window (XP dos):
ipconfig /release
If it gives you any error, post it here.
then
ipconfig /renew
Could take a minute to complete. If it errors, post it.