Your bylaws should say when newly elected board members take office. If it's not immediate -- ie they take over at the end of the school year -- then your current officers remain in place until then. Thus, the vice president remains acting president until the end of the current school year.
Whether or not the acting president can now become an elected president is also a bylaws question. Unless your bylaws specifically prohibit it (which is unlikely), it's OK for the acting president to run for president.
- Craig
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