How to reinstall bluetooth on my Sony VIAO with Vista?

I can see some of the fragments of bthxxx executable files (I guess that's what they are) but when I look in device manager it's not available. Nor from any other of the Control Panel options. I thought it was there at one time. I've been to all the sites and none of their answers help. Must be a way to re-stack or whatever to make it operate again. PS - I have the SP-2 update installed. Don't think it worked before that anyway. I've done all the F8 at startup tricks, none helped.