Help Please....SMC and Drag&Drop won't work

Just got a Sansa Fuze+. Trying to work it out.

In the instructions it says that I should be able to drag a file from the computer and just put it onto my mp3 player. I want to transfer BY drag and drop all of my stuff from my old mp3 to my new one, to save time, and also because not all of the stuff on my mp3 player is on the Windows Media Player. But when I go to drag into it ANY kind of music file, it says something about the device stopped working or is disconnected. So in other words, drag and drop, I can’t get it to work…

Then there’s the media converter. Half of the videos I drag onto the program, it brings up the box that says that the program has encountered a problem and needs to close. The other half the videos, when I go to convert them, it will start on the first video and it will not finish converting it. So none of my videos get converted.

Anything that can help me here is much appreciated. thx.