OK, let's try this the hard way one time and see what happens.
On the problem Windows 7 Computer
Click the start orb and type
ncpa.cpl
hit enter
in the resultant window, select then right click your wireless adapter and choose properties
in the properties dialog box scroll as needed, uncheck the box that says "Internet Protocol Version 6"
select (highlight) Internet Protocol Version 4 and click the properties button.
Select the radio button that says "Use the following DNS server addresses: and populate the boxes as follows;
Preferred DNS server: 8.8.8.8
Alternate DNS server: 8.8.4.4
OK your way all the way back out of there and see what happens.
To reverse what you've just done, just reset the radio button to Obtain ...