to godsaveusall,
i was in status all the way through. i never abandoned my visa status.
to mytreasure,
yes once u file ur i589, u will become an asylum applicant and ur previous visa status is put on hold. if u get rejected in the interview, u will reinstated on ur previous visa dn it will be resumed, providing that u have met all the requirements of ur visa category. if not, ur previous visa status is cancelled and u will be refered to court.
only the visitor/tourist visa will be considered invalid after their expiry date.
for visas such as f-1 or j-1, it is not just about their expiry, it is about meeting all the requirements of that visa type. so for instance if ur visa expires next june and u drop out next week, ur j-1 statyus will be considered abanodned next week.
regarding ur last question, i think u need to contact uscis and ask them what u need to do. or better yet contact an immigration lawyer that deals with student visas coz a lot of them don't. i know for to switch to certain visa categories, u need to leave the country and apply at a us consulate outside the states.
hope that makes sense.