no power after shut off

I have a 97 gp gt with 69k miles, last couple times i've shut off my grand prix, the key will not come out of the ignition, nor can i restart the car, nor do i have any power what so ever, no power locks, no radio, not even my fob works, i was wondering if this has something to do with a short somewhere or if i am somehow tripping the antitheft system? thanks in advance.

Check the battery cables and grounds,.

I agree with MAx. make sure your battery cables are clean and tight, sounds like a bad electrical connection.

I had a mechanic check the battery connections, and he said that they looked like they were solid, he didn't really run any tests or anything, is there anyway that i could test whether it's a bad battery connection? i mean when i lose power, i lose EVERYTHING, not even my hazards work. and it seems to boot right back up when i manually override the shift lock and move the gear shift around a little, everything springs back to life.

also it no longer just happens after i put it in park and turn off the car, today it happened as i came to a stop at a stop light.

you cannot check battery connections without removing the cables from the battery and looking for corrosion/dirt/grease both between the cable and battery terminals and the chassis ground lug/starter solenoid/ jump start post. A visual inspection just looking under the hood is like running out of gas, taking off your gas cap and smelling fuel, and determining you aren't out of gas.