dear roland partners

What exactly means "disk load error" . Could be possible that all of my system disks (4) are erased or damaged. I donīt think so....
So, could be possible a disk drive failure ?

How can I test , or fix it.
Could be a system "hang up", fixable by pressing some combination od keys ?

Iīm a w30 newbie, since i owned it by secondhand.

Thankyou, very much