network problem

I have 2 computers that are being networked up. Both are XP. I am using a wireless netgear router. I have set the network up. I will receive a signal and will be able to use the internet, but after 10 mins, the connection will be “unavailable”. The computer with the router is in the basement, and the computer receiving the connection is upstairs. When I get a connection, it says that the signal is strong. What is wrong? thanks