odd problem
you can try these things:
completely reset your router to manufacturers defaults
check if your router has the lastest firmware
try different wireless encryption methods (try completely open first)
if these things don't work...
then the chance is big there is something wrong with your notebook, but it still can be the router itself tho...
you can try to completely de-install the network-card including all the drivers, restart, install drivers again.
one other thing is: if you don't know mutch about wireless settings, never touch the advanced wireless settings tab! they can screw up you entire wireless network
I hope this works for you