macbook wireless range problem

my macbook is having problems with the airport wireless range. I cant connect from 50 feet away, but normally i can. i dont know what is wrong...can anyone help? is it possible that there is a hardware problem? maybe a software problem? i know its possible for interferences but i didnt change anything nor bought anything in the last 3 months. This problem started early to mid december. thanks

It really doesn't matter if you changed anything. It's possible that one of your neighbors bought a wireless router and it is using the same channel as yours. If that's the case, simply setting your router to use a different channel should correct the problem.

See the Wireless Networking FAQ for more information.