I Have A Canon powershot SD780IS And I Dropped It and my lens Was Out And Its Saying "lens Erorr Restart Camera" What Can I Do ?

It always comes because there is something loose inside the lens, such as a screw. These articles maybe helpful for you: Lens error, E18 error and turn the power off and on again Good luck

This is a common problem if the camera has been dropped. Canon can take care of the problem if the camera is under warrenty

The camera will need to be sent in for repair. Because of the age, you would be better served if you bought a new camera. For under $ 250 you can get the SD780IS which is smaller in size, has more pixels resolution and Image Stabization and many additional features you camera does not have.

Lens errors are fairly common. Usually it's sand or grit interfering with the lens extension mechanism. Or the camera's been dropped with the lens extended. Or the camera has been powered on, but the lens had been blocked preventing its extension. Or the battery ran down with the lens extended ...

Here's some things that you can do to try to correct it. They only seem to work for less than 50% of the 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

this is very common has the camera been near the ocean??? it does not have to be dropped to give you this error. repair on you lens runs 85.00 for repair. or a new lens for 125.00

buy a new lens because water stays in lens

somebody saying under warranty

http://www.digitalcamera-hq.com/digital-cameras/canon-powershot-a570is_question.html?qid=12688

I have the same model A470 camera ;it's says, " Lens error, restart camera".
How can i fix this?

Hello,
If this camera is under warranty you should carry it to the Canon Care Center they will replace the Zoom lens unit of your camera, or you need to get it replaced on payable basis as the lens has some strucking problem.
Regards,
Manoj Joseph
+91 9352008418

Manually rotating sensor rotor inside camera and cleaning gear fixed the Canon "lens error" for me.  
I placed instructions with photo's here: http://www.avh.dds.nl/Fix-Canon-SD600-Lens-Error/