wireless connecting problems

I have networks in the building where I live.

I used to be able to connect to both of them.  One is secured and I have the password or key.

The other is unsecured.

When I try to connect to them it says they did not respond to my computers signal.  I got this from  windows diagonsticks.

So now I have to connect at the library or coffee shop to unsecured networks.

Any ideas to fix this so I can connect again at home to the 2 networks?

I have an Inspiron 1501 with AMD Athelon X2 64 and run Windows Vista Home Edition.