problems with internet

I have an ibook g4, and my home has a wireless router. My mac mini will work with the internet service, but my ibook won't. Whenever I try to connect to the internet, I enter the correct WEP password for my router, and then I get bars or signals up on my top right screen, but when I open my browser, nothing. Sometimes, when I go into network assistant it says something like, your computer has a self assigned IP address and may not be able to connect to the internet. When I went into my settings I found an IP address, but there is no where to enter the address to unblock my computer. I have been on the phone with my service provider several times, and that doesn't help. Any suggestions?

Can you give us a bit more info? What router are you running? Is it set up for DHCP?

WEP is a very bad choice today for encryption as it's easily hacked into, but it should still work. Have you tried putting a $ in front of the WEP key? It's worked for some.

Which WEP are you using? 128Bit HEX? Ascii?

My router is set up for DHCP.
yes, i have tried putting a $ in front of the wep password before, it worked for like one day, but then it stopped working again. I am not using 128bit hex or ascii, it just accepts the plain WEP password setting.