Gateway IP address pop up

Hello,
hi i'm having some problems with my port forwarding. i know what my ip address and gateway address i have. but when i put the ip address in the browser i get nothing. and when i put my gateway address in the browser i dont get the pop up for my router set up. is there any way i can find out which router i'm using from the computer? or do i have to find it out manually? i am using wireless connection USB network adapter linksys but my router is not linksys. it is a shared wireless connection with 2 other computers in my house. i really need help getting the pop up thingy for my router. thanks in advance!