The screen reads "lens error, restart camera. I can not get the lens to retract. I can not get the power to stay on. The cannon screen shows up momentairly - but fades to black and the message appears.

Try the following steps when the lens is stuck and will not open, retract, or extend.

1. Turn the power off, eject the battery pack, and reinsert it into the camera.
2. Turn the power back on and check if the drive part of the lens moves properly.
3. If the lens still will not open, retract or extend, then reset the camera.

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 are some troubleshooting steps that you can try that may (or may not) correct it. They only seem to work for less than 40% of the lens errors, but if the camera is out of warranty (or repair cost approaches that of the camera), they're worth that try. Some of the later steps do involve some risk to the camera, so carefully weigh your options before deciding to conduct them:

It seems that either the plastic drive mechanism is worn/damaged, or the motor (possibly it's drive electronics) have failed. If an extended lens is bumped (or dropped) the plastic worm gear assembly suffers damage (easily too), and the mechanism cannot retract.

it shows lens error restart camera

Sending it to an authorized cannon repair facility. the lens must be replaced.

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 are 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.
　

Problem: dust in the gaps near lens which makes it jammed. Effect: the sceen shows blk color. Solution: just blow over it or vaccum it.

The lens motor is burnt out. Has to be replaced.

i had the the same lens error restart camera problem for almost a month.  If you haven't already, try restarting the camera with the sd1000 in the view pictures setting.  This may allow the lens to retract into position. Next, with the lens extracted, try looking down on the camera from the top to see if the lens is angled downward in any way.  If it is, this means it is jammed into place on one side.  Simply use your fingers to slightly push the lens into proper position.  If you hear a pop, you should be in business! hope this helps!

The following blog outlines some simple repair options for a lens error:

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