Connect my Dell Inspiron 1545 to my Sony Grand Wega KDF-55WF655

I am wondering if it is possible to connect my Dell Inspiron 1545 laptop to my Sony Grand Wega KDF-55WF655 television.  I went to Best Buy and another electronics store and both said I could do this.  I purchased a VGA to RGB cable where I connect the VGA plug to my computer and the RGB jacks to the Video 5 input on my TV.  I also purchased an RCA (red jack and white jack) that plugs in to the TV with the other end plugging in to my laptop for sound. 

When I hook this up, I get sound fine, but the TV displays a lot of distortion.  I can make out my mouse pointer moving on the TV, how ever it is also distorted and there's about 6 of them across the screen.  The distortion is in color.

I called Sony tech support and went through 3 levels of support only to have the last person tell me this wouldn't work and it had something to do with "interlace" and "progressive" scan.  I couldn't really understand what he was saying. 

Does anyone know if I can or can not get this work?  Please let me know either way and if it can, what I need to do to make it work.  THANKS!