I went over to my grandmas for a while, connected my laptop to her wireless internet, and somehow my computer changed the network name. Only I could connect to the internet earlier, while my grandparents could not. So after a lot of trying to fix this, I got my grandpas computer to work along with mine.

These are all laptops by the way. Now I need to connect my grandmas laptop to the network somehow, but I can't because it only detects the network about 15% of the time, and when it does, it just says "waiting for network to be ready" so what is going on? If you know a good site I can get an answer from let me know

Thanks

I take it you have tried powering the router down and buck up again?
Also try reseting the router with the switch on the back, BUT be aware... don't reset it unless you know how to set it up again.