Sqk, So you think the OS is the issue...Software issues are never intermittent. The scenario that makes a SW issue fail may need to be a specific way (set of conditions) but SW does the same thing every time. If it was working fine and all of a sudden started failing...that's a HW issue. I would definitely post the symptoms on the Casio forums, or call Tech support if you can.

If you re-loaded the OS, including any updates you got from Casio and it still fails, I doubt it is SW.

After re-reading your original post...if it were mine...I would take it apart, look for any issues....at least before you can it. If you have the knowledge, also re-seat any memory modules if they are in sockets (any chips in sockets, re-seat.

Oh, one other thing to try, lift 1 corner, hold it up, see if it fails, if not do each other corner in sequence...(putting some twist in the unit, maybe) if any of that fails, it indicates something loose or a bad connection. Reseat ALL connections you possible can.

BE DARN SURE you have it unplugged before you take the covers off!

Hope you can fix it...._