Hey -- I don't know how advanced your knowledge is, so I am throwing stuff out there:
Three things to try (Will keep an eye on this thread for your replies):
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You mentioned that you are able to "local only" resources. Are you able to connect to your router? Generally, this would be at 192.168.0.1 or 192.168.1.1
If so, you could try release/renew your DHCP license on the router to get it to connect to the modem. Although this is unlikely since you mentioned you were able to connect to the router/modem combo using a laptop.
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Next step would be to try to renew your computer's conncetion to the router.
1) Open a command prompt window (Start-->All Programs-->Accessories-->Command PRompt)
2) At the command prompt, type:
ipconfig /release
3) once done, at the new command prompt, type:
ipconfig /renew
4) close the command prompt window and try to connect.
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If that doesn't work,
(READ ALL OF MY NEXT TWO POSTS FIRST -- THESE IDEAS WILL NOT WORK IF YOU CANT TRANSFER THE TXT FILES TO THIS SITE). IF YOU CANT THEN SKIP TO THE LAST IDEA IN MY MOST RECENT POST. IF YOU CAN THEN PROCEED WITH THE FOLLOWING)
open another command prompt window and type:
route print > c:\route.txt
It will look like nothing happened. That's okay. Close the command prompt window and browse to your C:\ drive root. There will now be a file there called route.txt
Double click that file to open it in Notepad, copy and paste the contents into a reply post on this thread. That can give us information on what is happening and what to do next.
Good luck!!