I have a replacement screen and wondered if anyone has a guide?

You can download the user guide free from :

http://www.retrevo.com/support/Casio-EX-S770-Digital-Cameras-manual/id/918bh328/t/2/

User guide wont tell you how to replace the LCD.

Look at the following sites to get an idea:

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

Some useful sites:
http://www.myfixtips.com/blog/digital-camera/how-to-replace-lcd-screen-on-canon-sd870is-215.htm
The steps given are for different cameras, but it may help.

Hope it may be useful.

hi, you need to request to replace the lcd unit to the service center.

Hi there just like to informed you that 2 reason can make a noise.
1. low or old battery's using.
Solution: replace it if too old or charged it fully.

2. Lens error. Internal lens guide pin if damaged then the camera goes off with bad noise.

Solution: repair or replaced the lens guide pin.
Thanks & waiting for your feedback.

You may be able to find a screen on ebay. Otherwise you can send the camera in to Casio, and they will put in a new one for $50.
To remove old screen, remove all screws to camera, slowly pull it apart, then you will see screen and ribbon cable that attaches screen to camera circuit board. The ribbon cable easily slides out of screen and screen can easily be pulled off

We always recommended that you send them in for that.

you camera shutter is stuck at close position, you will need to open
the thing up to repair.

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As for the totally dark screen, either your LCD or driver board is bad. You will need to open and replace the broken part.

Hey i found this site that is great on how to change a LCD for the camera

http://digitalcamerarepair.googlepages.com

A new purchase? Reurn it to vendor for replacement

That is usually a physical repair job. Sorry. :( They can be reached at 800-706-2534 and then keep choosing option 1.