well did it shock u just the metal cover, or did u open it and it shocked u by an internal comprontent? if it was just the cover, throw the thing away...
high pitched sounds usually mean a vibrating/resonating coil or bad capacitor. the 1st is not bad its just annoying, but if its a bad cap then replace the psu. if this psu is a standard power supply, then you can test it out by shorting the green wire in the big 20 or 24 pin connector to a nearby black power. this will get the thing to at least turn on (if it works)... if it fails this test, then yep its the powr supply.