LCD SCREEN BLACK NO IMAGES APPEAR IN SHOT MODE

This sounds like it might be a defective CCD imager. If so, Canon should fix this for you for free, including free shipping both ways. This is regardless of your camera's warranty status. Please check this link for more info.

Applicable cameras include:
A40, A60, A70, A75, A80, A85, A95, A300, A310, S1 IS, S60, S200, S230, S330, S400, S410, S500, SD100, SD110, IXUS V2/300/400/430/500, IXY Digital 30/30a/200a/300a/D320/400/ 450/500

most likely the CCD imager chip is loose and cannot get electricity. Thereby cannot send an image to the main board in the camera. This is similar to an antennae not being totally connected to a radio or tv, and when you whack it the shock jostles the connection, showing some image or sound.

Canon specifically has a recall for all cameras with a sony ccd that seems to have a high temperature and humidity ccd disconnection problem, they repair it for free after evaluating it!

here's the link
http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=48264