Canon sd850 is cracked LCD

Sounds like a cracked LCD screen. You may be able to fix it if you can find a replacement screen. I usually search ebay for a broken camera with other problems that I can cannibalize. Here's some examples on LCD replacement. Don't recommend that you try this yourself, unless you have some experience and are comfortable with electronics.

http://camerarepair.blogspot.com/2007/11/fixing-or-replacing-broken-lcd-screen.html

Otherwise, the cost of professional repair is usually beyond the value of this camera. A better option is to sell the camera on ebay for other repair hobbyists to attempt replacing the screen for themselves. You actually may get a good price for the camera IF it's still capable of taking pictures.