Luna, it appears like you are having multiple issues. The overheating can be caused by a bad battery or the power management IC. The files not showing up can be firmware related as well as hard drive issues, so can the freezing. I would start by replacing the battery, reevaluate and see what it does. You can get a USB-to_zif adapter to check the integrity of your hard drive. Run the internal diagnostic test and see if it passes all those. Hope this helps, good luck.

but sometimes.i think this is NOT caused by overheating or something.before i have this fault,too.i just have 32 song.it still normal.secong time,i sync with itunes and i have about 10 songs or less.the third time,i syce with itunes too and i have about more than 200 songs.BUT after that,sometimes i try to connect with pc and it can't and now,when i try to recharge by plug into a power outlet(you know it,i think) and it cannot recharge.BUT when i breaking up the source at the ipod source.it charge BUT when you using.it cannot charge.you must turn it stand by by hold the play button for a few second.so it charge.works for me.