have you tried to configure the iMac manually, instead of using DHCP?
(you've probably gone thru this w/ the Linksys support) open up TCP/IP and choose configure "manually" where it is now "use DHCP server"
IP address: 192.168.1.4
Subnet mask: 255.255.255.0
router: 192.168.1.1
input the DNS info if you have it in hand as well. w/o the DNS servers, you won't be able to browse the net, but u can open your browser and type in 192.168.1.1 in the address bar and check if you can finally communicate w/ the router.
if this don't work, then you're off to "hard reset" your router. there's probably a button on the unit that does it. look it up in the manual.
if resetting also don't work, take it back and get a netgear. mine works great. even when i screwed it up bad with an invalid subnet mask, a hard reset brought everything back to normal.
(you've probably gone thru this w/ the Linksys support) open up TCP/IP and choose configure "manually" where it is now "use DHCP server"
IP address: 192.168.1.4
Subnet mask: 255.255.255.0
router: 192.168.1.1
input the DNS info if you have it in hand as well. w/o the DNS servers, you won't be able to browse the net, but u can open your browser and type in 192.168.1.1 in the address bar and check if you can finally communicate w/ the router.
if this don't work, then you're off to "hard reset" your router. there's probably a button on the unit that does it. look it up in the manual.
if resetting also don't work, take it back and get a netgear. mine works great. even when i screwed it up bad with an invalid subnet mask, a hard reset brought everything back to normal.