I recently purchased an older home and the stairs, original hardwood, squeak like crazy. At first I thought they might be great to keep an ear out for intruders or my soon to be teenage son sneaking in late! But...After a year or so, they only prove annoying.
Heres the problem, there is no access to the underside of the stairs. None whatsoever...It may be possible to build an access door, but I have no idea what might be on the other side.