Laptop wifi finding other networks ,but not all.

Hello, I will try to explain the situation. I am working in office with business partner and both have laptops and conected to network via wifi. About one month everything was good ,I was conected to network,but one other day laptop don't find what wifi network,but friend laptop is finding it well. Also my laptop finds many other networks ,but what one which I was using not find. I dont know...