Take apart nikon d200

SOURCE: Nikon D200 Water Damadged

It can be repaired, but usually water-damaged cameras are either worthless or VERY expensive to repair. I should expect that yours is destroyed, since Nikon's D200 is not designed to be waterproof, and has many electronic and steel parts which are very susceptible to being destroyed by the infiltration of water. A good camera shop would give you an estimate for no charge. If they tell you that it is beyond repair, you might take it to another shop for a second opinion. Is it possible for you to claim the damage on any insurance? You might check with your insurance agent just to be sure.

SOURCE: registering my new D200 nikon camera

Go to NikonUSA;.com, click on "Service & Support"; select "Product Registration".

SOURCE: nikon 18-200 mm vr lens not auto focusing on my nikon d200

lets start with the basics, try hard reseting it and try again, if that doesnt work then
try upgrading your firmware (if possible on your camera) and if that doesnt work then it may be the lens, but dont forget to spend a few hours trying to find a option for it in the meny