Can't get WiFi routers to work.

[Outrager]

I currently use a D-Link wired router to connect to the internet with my RoadRunner cable modem, but recently bought a laptop with WiFi and thought I should upgrade to a wireless network. I have tried 3 WiFi routers and all 3 don't work.
First I got the Linksys WRT54G. When I plugged the cable modem into the router, the cable modem's PC LED wouldn't light up.
Second, I got the Netgear WGR614. When connected the PC light on the cable modem would blink sporadically instead of staying solid so the internet would be on and off and in general annoying.
Third I got the D-Link DI-524. When I connected the router and cable modem, the PC LED would only light up right when the router is plugged in. It would blink a few times with the WAN LED on the router, then both would stay off.
However, if I have the wireless router connected to my wired router the WiFi would work fine.
Also, the cable modem's PC LED doesn't seem to come on when I connected directly to the PC either.

 

[Phaedrus]

Very confusing. Since plugging the PC into the cable modem doesnt light the PC led, then it would stand to reason the router wont light it either. Have you tried resetting the cable modem and router? Have you tried any configuration or are you just plugging the stuff in and it isnt working? Are you using the wireless routers in conjunction with the dlink wired router? If you already have a router, you might try just a wireless access point instead of a wireless router. Or just use a wireless router by itself connected to the cable modem(the wrtg54 is router and access point doesnt need an additional wired router). Give us some configuration settings these things arent always plug'n play. Do you need to clone the mac address with the wired dlink?