Hi, if you click on the wifi icon on the pc upstairs that looks like a box with brackets coming out this will bring up wireless networks. It is possible that although you have found the router you may not have set the security up on the pc upstairs as you did down stairs and this could cause limited or no connection.
If you type in the netgear routers address into the search bar of windows explorer which if i remember correctly is 192.1668.0.1 and you can log in to the setup config of the router then you may be able to resolve the problem. if not netgear have a very good back up faq site worth loking at. I hope this is of some help.