Go to a stereo shop or Best Buy'* Install Bay and ask if you can borrow there keys for removing the deck or ask if they have an extra set.
Most of the time they have tons of extra keys laying around cause they forget to give them to customers or they don't want the customer playing around with the radio after its installed.
Take the trim ring & face off first. Use 2 small flat screwdrivers and go in along the sides of the deck and push inward on the handles, then grab the frame of the deck and pull out.
92 Bonneville SSEi - Stock - Remaining repairs needed due to neglect by previous owner - ABS/Trac, AC.
Mods so far: Maganflow High flow Cat, Rebuilt */C
Future Mods: Interior swap for Leath, High Output Altenator, Crazy system, Climate Control swap & Custom Exhaust/Intake.
98 Dodge Stratus - Wifes Daily Driver
92 Dodge Shadow - My Winter Beater