Keyboard problem - Left 'shift' key doesn't work with 9, o, l keys

I have an Inspiron 17r and the left shift key has all of a sudden stopped working with certain keys.  I can use the right shift keys and they work fine.  I have turned it upside down and blown the keyboard out with compressed air to no avail.  I have used a wireless keyboard and it works fine.  I would appreciate any other suggestions before having to install a new keyboard. 

I am just one month out of warranty :(

Thanks!