unfortunately I'm limited by my phone, so can't actually see the picture you have posted.
Firstly, if the board is too far gone then its going to need a pro to look at it, examine the damage, then do the necessary in those areas.
However, you can occasionally revive a dead board by simply dislodging some of the corrosion if that corrosion is for example creating a short..... the easiest way to do this is with an ultrasonic cleaner. Decent cleaners use a sweeping frequency to make sure they clean everything up nicely. using a pcb cleaning fluid along with distilled water will help, as will using it warm (about 65 celsius). after that, soak in 99.9% isopropyl alcohol to displace the water, and allow to dry. give it a whirl you might be...