how do i know if my 97 ssei has an alarm or not when i bought it it didnt come with a remote and the guy i got it from doesnt know much about it just bought it and drove it ??any help would be awesome (p.*. i have locked it and ''tried'' to open the door only trhing that happend was my interior lights came on i havent tried to further set it off cause well i have no remote n i dont wanna mess with my computers mind

Locking the doors manually and attempting to open them will not set the alarm off. Even if you left a window open and hit the unlock button, the alarm will not go off.

To verify if you do have keyless entry, verify that you have metal contact pins in cavities 8 and 4 of your OBDII diagnostic connector.
Here'* the info about it....
https://www.gmforum.com/electrical-133/program-keyless-remote-96-99-a-278809/

Put your windows down, lock the doors and then pull the handle open through the window. I did it by accident the one day and my alarm went off.

Yep!, Been there, hate that. LOL!

Locking the doors wont do that. You need to lock with the FOB with the drivers door open, then close the door. If you then reach in and open the door from the inside the horn will sound.

Yea, what we said.

Mine works no matter what you lock with. If the doors are locked and you reach in through an open window and pull the handle it goes off.