This only happens when the laptop is connected to a projector and smartboard or does it happen at other time also?

Is it direct wired or wireless to the smartboard?

By the way have you tried a can of compressed air to see if something has been blocking the keys movement?

Does it reset itself after the stickykeys have been turned off and then back on?

Use the following to turn on the stickykeys and see if it helps a bit better...
press fn key 5 times in a row...... this works on some keyboards to reset the fn functions and sometimes brings dead keys back to life!