2 laptops on net, both vista

[LichIsTheManHa]

First off, let's start with the specs.
We're both using Compaqs.
We both are running a Windows Vista Home Premium Service Pack 2.
My friend just upgraded from 1.
At his house, I can get on his internet with no problem.
And the last time he was here, he could get on with no problem.
Now, he can get on, but has no internet, same as my brother with his mac from school. (That's something else I could make a topic for...anyway)
He couldn't get on with SP1, and he just upgraded to SP2 with no luck.

Is there anything we missed?

Edit:
Belkin wireless router.
I forgot the modem brand.
Cable...DSL
And obviously we have our wireless buttons on...they turn on automatically.

 

[Blackhawk7188]

Try power cycling the entire network and all devices. This usually solves most problems. Restart the wireless on the laptop also. If you still cannot connect "diagnose" the problem and have it make a new IP address for the notebook. Last resort, you may need to do a reset of the modem/router combo and have it go back to factory settings and work from there.