Repair is considered non user serviceable so get estimates.
However this looks to be a decade plus old camera as http://www.cnet.com/products/nikon-coolpix-8700-digital-camera-series/ is from 2004. I'd forgo any repair and start shopping.
http://www.ebay.ca/sch/ctg/Nikon-COOLPIX-8700-8-0-MP-Digital-Camera-Black-/100167008 finds about 100 dead cameras so this means it's at the end of expected life span. I do not advise repair.
Bob
Hello. My Nikon 8700 coolpix viewfinder screen in completely white. The electronic monitor works fine though. Can anyone tell me why it is white and how I can fix it?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic