Can't load or save on Internal Disk

Since I installed JJOS2XL as Trial on my MPC1000, there is this issue with the Internal Memory. As you can see in the pic, the part of the screen appears "glitchy". I can't load or save anything on it. Formating didn't work too.
It always says "System Error". I also tried too reinstall the free JJOS.



Are there other ways to reset the whole MPC? I do not have a manual so i don't know.

Thanks!