Wireless problems.. Help me pls

I have just recently changed my router to a BT business router 2700. For the first few days my laptop never had a problem at all picking up the signal.. then yesterday morning I could not even detect the network at all. I have been trying to work out what the hell has happened, as nothing was changed.
 
I have a intel pro 2200bg wireless card on my laptop. From what I can tell all the drivers are upto date etc. And all the settings are correct, I have been looking on forums but can't really find anything useful that can help me.  
 
I can see other wireless networks around me, when my neighbor used his laptop he connected to my network no problem.. I made sure nobody had changed anything on the router and everything seemed fine. I am now connected through next doors..
 
Has anyone had any simelar problems or any ideas?

restart your modem and your router, see if you can connect. 
 
If not, login to the router to see if any settings have changed.

simelar