Hi. Don't know if this will help, but I had something similar happen after updaing my clip's firmware. I have a 32 bit Windows 7 OS.
After discovering trouble with my clip no longer being recognised by MP12 and showing up as a drive with a drive letter I found the USB setting on the clip had been switched to MSC. I tried switching it to MTP & then to auto & found Auto worked best. Although I can't get the taskbar icon to show automatically I have found that once the clip is connected if I go to devices & printers & then to the Sansa Clip icon & click on it the screens you refer to come up. Not an absolute fix, but at least it's a work round.