songs play in slow motion

Many, many people have the latest firmware, including me, and do not have this problem.

You could always try downgrading. Go to the firmware update thread  and right-click on the All Regions link for your firmware version (1.x or 2.x). Copy Link Location, paste it into your browser, and change 1.02.31 to 1.02.28 or 2.02.33 to 2.02.28. Download the zip file, unzip it, drag fuzeA.bin onto the driveletter that says Sansa Fuze and it will install the older firmware when you disconnect. 

That will tell you if it’s the firmware update.