Using a wildcard Find/Replace, it could be done with:
Find = ^m*MyWord*^m
Replace = nothing.
Do note, though, that any manual page breaks within the Section will cause the Find/Replace boundaries from wherever 'MyWord' is to stop at that point. It also won't work on the document's first or last Sections.

There are other issues to consider too, quite apart from the formatting & header/footer issues raised by Charles & Fumei. For example, if whatever process you're using to create these Sections does not always enclose the insertion in two Section breaks, or if the insertion has Section breaks of its own, you'll run into problems, some of which will be insurmountable with a Section-based approach.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]