could be a bad CF card. they are getting pretty old. i've had to swap a few out
you can also remove the computer motherboard and remove/reinstall the ram,flashcard and see if that smartens it up...check the board for capacitors with bubbled tops...they will need to be replaced.
your power supply might be going south... lots of times the capacitors go bad on those and let tons of ripple into the computer causing all sorts of issues.