Sony Walkman NWZ-S616F mp3 player-a few problems?

[Jungle Jane]

I got this for Christmas, please don't tell me it's garbage and I should get a different one or whatever, it was a Christmas gift and I need to make it work, don't have the choice to exchange it.

My question is that some of the files that I was able to listen to on my previous mp3 player (a crappy ILO-now discontinued Wal Mart brand) won't work on the sony. When I try to sync them I get a "!" symbol and it says "error". Also some of the pics I can view on my computer fine but when I try to view them on the walkman I get an icon of a picture torn in half, tells me the file is no good but I can view it on my computer??

Final question (for now) some of the songs end abruptly just a few seconds before the song would normally end. Not the end of the world, but doesn't make for nice listening. When I listen to the same songs on my computer I hear the whole thing.

Thanks in advance to anyone who can shed any light on any of this.
-Jane
Also-when I try to sync using windows media player it tries to sync every thing on my computer to the mp3 player, not just the files that I've dragged and dropped to the sync side bar. Any ideas what I'm doing wrong????

Can you tell I am NOT a techie girl???
hey youngmec--
vixy.net is the converter i was told to use, haven't tried it yet. supposedly it's good but sometimes it's busy. good luck and thanks for answering!

[youngmec2008]

I got the same problem but the songs on mine are working and play all of the song. The cd that came with the mp3 player has a converter so download it and it should convert all the songs on your computer to an mp3 format. The only problem i got is that the videos i downloaded from Frostwire won't go on mine and i tried a lot of converters but they don't work so do you know any good converters? If you don't then thanks anyways.