Question: I think I have a ghost. Am I crazy, and what should I do about it?
Answer: No, you're not crazy. Lots of places, not necessarily old houses, hold energy from the past. There are many reasons why this can happen, and it doesn't necessarily mean you've got an evil entity lurking in your attic. The first thing to consider of course, is what kind of activity you're experiencing. Take some time to keep at least a mental list of what happens, when it happens, and who's around when it does.
Call in a plumber, check batteries, even things like train or subway schedules if you live near one. Ask other family members to be aware. If does happen that you find there're things happening that can't be explained by rational explanation, don't panic. Consider if any of your own family members or loved ones have passed. Investigate the history of the property, if possible.
Consider as well the geography of the place. Here in New England, for example, there's a lot of granite in the soil, close to the ground, and, in our cemeteries, slabs of it. Granite is especially good at holding energy vibrations, so not only are there a lot of houses in New England full of history, but a lot of those houses are sitting on top of foundations or on ground full of what amounts to energetic sponges.
I've lived with a ghost for the last eleven years, and it's perfectly possible to come to an understanding with residents who refuse to leave. (there could be many reasons - including the nature of the haunting itself - why you may need to learn to either accept the haunting or move out.) Most intelligent hauntings - ie, ghosts who can be interacted with - can be reasoned with, in my experience. On the other hand, if you are truly frightened, don't hesitate to call in practitioners who understand how to work with negative energies. One of the worst things to do in the case of a truly malevolent haunting - rare as they may be - is to deny what's happening.
and furthermore, the war will end. blessed be.