C25's do not have a dagger board.
There are 3 keels you may encounter:
Swing Keel
Fixed Fin Keel
Fixed Wing Keel
Unless modified or a late model, you either have a swing or fin.
From what little you describe, you have a swing keel. So, what is the problem? Is it stuck down and you can't raise? Stuck up and you cant lower it?
The swing keel must be inspected annually, with the mechanism replaced every few years. A failure resulting in a keel drop can be catastrophic, even resulting in sinking of the boat. Work needs to be done out of the water, so the boat needs to be hauled and put on stands or a trailer.
Come over to our
Association Forum, register, introduce yourself and ask any questions you may have. You will find the swing keel has been completely discussed many times, so take some time to search and browse the many threads on the subject. You'll find complete instructions on maintenance, replacement, and inspection of the swing keel mechanism, including pictures.