Making me a little crazy - My Kindle Fire 7 HD used to be recognized by my computer. I have Calibre and could add books whenever I wanted. I was unable to use computer for a few months (4) due to health

and upgraded to Win. 7 when I got back on. Kindle is no longer recognized. Unknown device is what it says in Device Manager. USB port works with Iphone, cable works for charging but not data exchange. Kindle cable. I'm frustrated and stumped. I've downloaded Drivers and APD. Device manager says drivers current. Did Kindle come out with a new update in the last 4 months? That is the only reason I can see why the same kindle won't work on PC. Not real savvy about PC's and not real patient with this Kindle issue (have been exploring fixes for about 3 weeks now.) Could someone point me to the right thread or something that will work?