some problems with network..(srry ima beginner)

I am not really good with networks and all of that.. dont really kno difrences between switches or routers or w/e that stuff is... but i am trying to connect my laptop to our internet.. so, I had DSL internet, and my DSL modem and my linksys router were connected so that i have internet on my desktop, and my laptop could catch wireless too.. modem connected to internet, the ethernet cable went into my Linksys Broadband router WRT54G into the INTERNET slot, and another ethernet cable from one of the 4 slots from the router went into my computer... the internet worked fine, everything worked perfectly.. now we got rid of DSL and got cable.. So we got the modem for our new cable internet, (http://www.simplehelp.net/images/cable_modems/motorola_sb5120.gif), and i tried doing the same thing with it to... the cable internet was plugged into the modem, the ethernet cable went from the modem to the router Internet slot, and from the router i have another ethernet cable going to my computer.. almost same thing like with dsl except now i have cable, and a new modem... BUT now the internet doesnt work... it says that i have the local connection, but i dont have internet on niether my desktop or the laptop.. dont kno wats the problem.. i tried going in to my linksys options or something, reset everything to default and stuff, and still no progress.. tried troubleshooting to c wat the problem was, and my comp says that even it doesnt recognize it... help??? srry if i explained in a confusing way... isnt my native language lol...

 

well no one knows wat to do?? i tried updating my router.. also googled and changed some things in regisrty like mircrosoft told me to.. still doesnt work.. i get this error when i troubleshoot for internet now...
*There may be a problem with the Domain Name Servers (DNS)

Windows attempted to find the well known host "www.microsoft.com" using DNS. The server responded that the name was unknown.*

 

how about working backwards, hook the cable to the modem then connect the modem to the computer and see if it connects. once you connect. get your ip address. write it down just in case you need it for later configuration...

if it connects then you move onto the router. connect it as you had it before. open a browser type in 192.168.1.1, this should get you to your router settings.

in the setup tab the first drop down menu should be automatic dhcp

your local ip should be 192.168.1.1 the default mask should be 255.255.255.0.
the rest of the settings you can follow through using the below link.

pdf linksys wrt54g setup

 

the modem connects with the computer and internet works fine, but when i add the router to it, the internet doesnt work... those instructions explain how things work... but it doesnt show me how to fix my problem.. plus it shows for windows xp and lower, i have vista... my router is somehow blocking the internet connection, theres like a firewall or something that doesnt let internet go through... tried disabling things in router at 192.168.1.1 but still no improvement... grrr