If anybody out there is knowledgeable about home networking issues, I'd really appreciate your help.
I moved into a new apartment about a month ago, got internet set up through Comcast to make sure they'd have the service turned on when I lugged all my equipment into the new place (of course they didn't actually do that until after I had to call a Comcast installer out there to the tune of $50, but anyway), only to have it go down about three days later. Then I had to go out of state for a while without having it fixed first. I just returned last night and 'fixed' it myself, to whatever extent unplugging something and pressing a button can be called fixing something. I am using their provided router to connect the desktop via ethernet cable.
The problem is that while my desktop is working fine now, my laptop apparently still thinks it's at my old apartment (just as it did for the brief period when the internet was sort of working on the desktop, before I had to travel out of state). It is set to the network I had set up at my previous residence (which worked fine there), and does not recognize the setup done by the Comcast guy. The weird thing is that while they are now both on different 'home' networks (with different IPv4 addresses, so it's apparently not just a matter of renaming the laptop network to match the generic "Network 4" setup by Comcast and then having the desktop search for it, as several sites suggested), the laptop (a Dell running Windows 7) still says it has an excellent strength signal, despite not actually being able to connect to the internet.
What can/should I do about this? Is it as simple as trying to release and renew the IP address on the laptop? That's what another site recommended trying, but it didn't help the situation.
Oh, and neither command prompt lists either connection as DHCP enabled, if that helps. I don't know how to do that.
Please, if anyone can help, I'd be really grateful. I don't even know what any of the above means (or if it's the right info to give to fix the problem), I just know that everything was working fine at the old place and now it's not, but neither network seems to have gone away...they just sort of exist, side by side, and only one of them can connect to the internet.
Thanks in advance for any advice.