Sample memory time not loading up when turned on.

My sample time/memory doesn't load up when I turn the 2000xl on. When i go to the sample screen I have no time to use for samples or for loading sounds from my zip disk. Do I need an OS disk to replace/re-boot? Who else has/had this problem and is it fixable? Note- It sometimes loads the memory time but if the MPC is on for more than bout 30 minutes the unit emits static noises and starts randomly playing all current sounds. lol
fixes anyone?