My Canon PowerShot SD850 IS has a lens that is stuck in the extended position. I get a screen that says lens error, restart camera, but when I try to connect to the software, I get a screen on the computer telling me the computer cannot detect the camera. Battery is freshly charged, and I get the little yellow bird picture on the camera when I turn it on. It beeps about 4 times, and then turns off. Is there a safe way to get the lens to retract?

Try these procedures.

Try the procedures in this tip.

Are you certain that it's not saying instead "lens error, restart camera"? If it is, 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.

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 ... Unfortunately, many cameras that fall prey to this can only be corrected by professional repair. But, here are some things that you can do that may correct it. They only seem to work for less than 40% of the lens errors, but if the camera is out of warranty, they're worth a try.

This is probably THE most common failure among digital cameras. There's a halfway chance of fixing it yourself, described here: http://camerarepair.blogspot.com/2007/12/fixing-lens-error-on-digital-camera.html

that could be the lens cover not opening all the way, try and look at the lens as if you were doing self-portrait, and power on. if lens cover opens all the way but lens doesn't come out, the lens might be stuck or motor broke.

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

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

Lens error is usually caused by mechanical faults concerning lens assembly. The lens cannot extend or retract fully, the error is detected and lens error is returned.
Sometimes this can be fixed playing with the lens during extraction or retraction to help the lens asset getting back to normal.
More often the camera lens must be disassembled and re-assembled by a technician to fix the problem.

Defective mechanism, a stucked mechanism is present. camcorder are smart it can detects error and shuts down itself for safety. earlier models dominoes the defect if the user is not quick enough to react when something goes wrong with the camera. You need professional service to fix it.