To open the trunk, for a 1993, next to the steering wheel there's a button that says tailgate open, push it. Then go to the back and where the spare is attached to there is a lever on your left that you have to flip towards you, flip it, and at the same time there's another lever right behind that spare you have to pull towards you. that releases the spare away from the door, the window should open and with the spare out of the way you can open the door.
You can't unless it has a remote trunk popper on the unlock remote. I had the same problem and went to an Isuzu dealer for a new key and remote.
Behind the driver's seat there is a trunk release that works with the ignition key.
There is a manual release behind the rear seat, fold the seat down to find it, than have someone push the trunk release button. If this dose not work it may be broken.
Usually they are in the glove box, but they could be located on the floor, in front of the seat, on the drivers side, or on the drivers door itself. The 1998 Buick Regal unfortunately does not have a manual trunk release. There are kits available to add a manual trunk release, however.
Glove Box
Owner's manual or keep looking. Maybe it does not have one. Look at the trunk lock and see if it is manual or electric.
There is an auto trunk release on a 2004 Grand Prix. If you push the drivers side door lock button to the left and hold it, the trunk will open.
NO, only button it has is on remote and manual open on trunk door, when car is unlocked.
Check in the glove compartment.
Look in your owners manual.
Read your manual. There is a switch in the glove box to disable the trunk release button on the dash. you lock the glove box with the regular key. When you give someone the valet key they can not get in the trunk.
Look in your owners manual and it should tell you.