Lost connection to wireless network

Hello,

I was able to connect wirelessly to my MS Wireless router for over a year,
however recently cannot. I've connected outside of my home, so I know it
must be my router. I've changed 2 things recently - first, I turned on my WEP
security. I've since turned it off, and still cannot connect. Second, I've
switched my ISP to Comcast.

I've noticed when I repair my connection, the IP address given via DHCP is
NOT within my secure addresses. If I manually assign the IP address, the
icon shows connected, but my internet connection does not work, and I'm
unable to ping the base station. Any thing else I should change or try?