Just replaced my Belkin G with a new Belkin N due

I had such a problem recently with a terrible time staying connected. The problem was traced to poor channel selection. Even though I chose an unused channel, I picked channel 8. Apparently this is the absolute worst channel for interference from microwave ovens and cordless phones. Even though there was already someone using channel 11, the signal strength was only one bar. I switched to channel 11 and the problem went away.
I had done the same thing as you did, initially. I bought another wireless adapter only to find the same thing happening, which forced me to find the solution described.

hi,

here is just a suggestion,
the modem you are using have its own transfer cable, connect it first, directly to your notebook LAN card.

connect to internet, if you can browse well then it is a good network connection., check also if there is still intermittent connection.

in this stage might be better to check what IP address of the notebook lancard you are using , and note it down.

assuming you have good wired connection, the next step would be connecting your router.

the set up would be modem to router to notebook

if you can browse again to the internet, it means you have a good network connection., now try to open the Belkin configuration utility
might be, type in your browser 192.168.2.1, log on , check the wireless connection, and have your notebook IP address checked and unblocked.

to further check if you have successfully configured your wireless card, remove the wired connection, connect to the internet and browse again.

hope i have helped you, thanks for using Fixya!