My MP has trouble saving/loading....help!!!!

ok so my problem is that everytime i load my programs and or my sequences 3/4 of the time it will tell me that it is "wrong file" or "missing data"...i have tried many times to reformat my flash card and my 80g harddrive and it still does not load correctly.......my suspicion is that my mpc needs and new power supply...the reason why i think that is because when i turn the mp off and it makes a (EWWWW) winding noise 9 times out of 10 the data has once again been scrambled....and when it does not make a noise the data is fine when i load it...my question is: does my mp need matennince and be sent away or am i "kinda" right that it is the power supply...if im right can i just get any power supply from a comp. shop or is it akai spec.?.....help me please....

Im guessing that when you hear that "ewwwww" sound it's the hard drive spinning down. Wait for it to stop spinning before you turn it off instead and see if it still makes that noise.