Help me Avoid making a fool of myself......

Tonite after hanging out i went to my car to head home only to find that i couldnt unlock my door. After all of my friends had a turn at trying to unlock both my drivers and pasenger side doors, the driver's side door eventually unlocked. The passenger side door lock remained frozen. I have ruled out it being a bad key since i was able to open the trunk with no problem and i used both of the keys i had on me in both doors.

I can not figure out why my passenger's and driver's side door locks do not open with either of my keys. Once inserted in the key hole the key will not move at all. The driver's side door eventually unlocked after a few minutes of trying.

the car is an '85 190e
any ideas to how to fix this would be greatly appreciated


thanks
doug
'85 190e 181k