Can't connect to internet at home, but works fine in tech shop

[T20]

Got a weird situation with a compaq desktop. I upgraded the system memory to 1.2gb for a woman. She took the unit home, everything works fine, except she can't connect to internet. I got the unit back, and it connected to the network fine. The desktop still can't connect to the internet even after I did a complete system restore. Comcast agreed to replace her modem with a new one, and her friend's laptop can connect to the internet fine. She told me that the network connection showed connected, just when using IE, she got no server error. I tried the desktop with my network connection and I can surf the net with IE. Right now I told her to bring the desktop to her friend's house and try it there. If that still doesn't work, I'm out of idea. Any suggestions?

 

[Electrofreak]

Only thing that comes to mind is a DHCP issue involving a MAC filter on the router...

Is she getting a proper IP address and not an APIPA?

 

[T20]

No router, it was direct connection to the modem. Although its one of those with telephone jacks in it, don't know if that makes difference or not.

 

[Electrofreak]

Heh, I always thought Comcast was a cable internet provider only... didn't know they did DSL.

 

[T20]

umm...Comcast is a cable company The phone jack i was talking about is for voip telephone service.

She told me that the computer got a connection with the modem, its sending data to the modem, but nothing back from it.