Help. freezing like this

I like this cute device but recently it becomes like below (Japanese language means: database) after I cut the USB line from laptop.

Anyone has advice for me to solve this problem? I read some advice such as press the power botton together with the down botton and it shut down but when I click power botton again, it pop up with the clover screen and shows below words again. 

I didn’t install rock box. Do you suggest me install it? I have a disc in package it says: Rhapsody. is it rock box?

If I install it, should I install it on laptop or sansa? Sorry I know my question is a little bit silly.

Thanks in advance!

Thank you very much for your specific advice.

I restarted several times, it always stuck like that. No process anymore at that position. It shut down itself after several hours.

Maybe there are some files not easy to read stored in it cuz there was a song, everytime I play it it shut down itself. I forgot which song. I will delete all files in it and see what happens: )