Connection when router is involved

My MBP connects fine to home and public wireless networks; however, in my church there is a router in between the wireless access point and where the ISP access point is. The frustration is that others will enter the room and immediately connect. My MBP, on the other hand can't seem to negotiate connection. Other systems range from iPads to PCs. I spent considerable time trying to trouble shoot access to subnet, renewing IP address.... Spotty results. Can/should I return system to default settings? Would that help it negotiate connection. MBP "sees" the wireless network and allows me to connect, but I am not connecting to the internet after that. Running OC 10.6.6