CANON A75 - dropped it!!

Check that the lens cover is removed before taking pictures.

The purple screen is also an indication of sensor failure, However, the odd noise could any of a number of things from sand/gunk in the gear mechanism, a damaged tooth on a gear, etc... But still, recommend that you contact Canon to arrange the advisory free repair (with free shipping) of the sensor. Call 1-800-OK-CANON.

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 the following two links for more info:
　
http://camerarepair.blogspot.com/2007/11/canon-digital-cameras-showing-black.html
　
http://www.usa.canon.com/consumer/controller?act=PgComSmModDisplayAct&fcategoryid=225&modelid=13390&keycode=2112&id=29819

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 200a/300a/400/450/500

CCD is dead. Very common problem.
Needs new CCD.

Its bad ccd imager in camera and this part will be replaced.
Canon will repair Free of Cost A75 camera as per announced scheme.
Click Canon CCD Imager Advisory for details.

Here are some simple things to try first for a camera that won't power on. They won't work for every case, but they're worth a try:

http://camerarepair.blogspot.com/2007/11/simple-fix-for-dead-cameras-that-wont.html

Hi,
Your Canon A75 camera has problem in CCD Imager Sensor. Canon announced scheme to repair this fault free of cost. Click Canon CCD Advisory for details.
Bye.

See this link.

Here are some simple things to try first for a camera that won't power on. They won't work for every case, but they're worth a try:

http://camerarepair.blogspot.com/2007/11/simple-fix-for-dead-cameras-that-wont.html

If the above don't work, then you may possibly be experiencing a lens error. Here's some things that you can do to try to correct it. They only seem to work for about 50% of lens errors, but if the camera is out of warranty they're worth a try:

http://camerarepair.blogspot.com/2007/12/fixing-lens-error-on-digital-camera.html

Here are some simple things to try first for a camera that won't power on:
http://camerarepair.blogspot.com/2007/11/simple-fix-for-dead-cameras-that-wont.html