First of all, check that the projector / whiteboard is out of warranty. They usually are purchased with extended warranties beyond the common year, usually either three or ten years. Secondly, if they are out of warranty, then check the obvious, is it a break in one of the data cables for the whiteboard? Is the bulb for the projector faulty?
If you've checked common faults, and that didn't fix the problem, then it's time to get the whiteboard repaired.