Strange Airport Difficulty wireless problem!

First choice

So your first choice is to connect to the router with a network CAT5 cable? is that correct? And your MBP will not play nice connected that way?

 

You need to log into the admin side of the router (your 192.168.1.1 or whatever it is for your model) and check the following things on the Wireless Connectivity/Security tab:
1: You have wireless access turned on
2: You don´t have it blocking all unknown MAC addresses without your MAC address being inputed.
3: Either make sure its being broadcasted or that you've got your MBP looking for your network name
4: Try using different security if you can WAP or WAP2.

If none of those work, and you still want to connect wirelessly without security
1: Allow only one computer to connect at a time.
2: Add your MAC address as the only accepted one.
3: Create the longest, most random network name possible, and turn off the auto broadcasting.

I would definitely use it sparingly that way and never to send secure information. And if none of those are options/work, then using the Ethernet is the safest.

Best of Luck.