Door latch

Got up this morning to drive to work in my 1999 Prizm; unlocked the door with the remote key fob, got in the car but the door will not latch closed. I tried a little WD-40 to loosen things up and thought it was perhaps that it was just the cold(25 degrees out). There seems to be something more sinister going on though. The inside latch handle no longer feels as though it is attached to anything. I pull on it and there is no resistance. It was very embarrassing having to call my work and tell them I won't be in today because my car door won't shut. What is this issue and how do I resolve it?

I'm guessing you've done the repair by now but just in case or to help others with this problem which seems to be somewhat common, even though I can't find it in a search, I seem to remember other posts about it.
There is a small plastic connector behind the door handle that breaks. I think I had to go to the dealer for the part. If I remember right I didn't have to remove the door panel entirely but it was a pain working in the tight space. Just pull out the door latch handle & you'll probably see part of the broken piece still connected. It would be a breeze if you remove the door panel but I have crank windows & didn't mess with removing the window handle.

the handles are made of plastic and plastic breaks easier in cold weather. you might just have to replace the inside door handle as he rod slips in a hole on it .if the hole has broken then the handle can't open the door. if just the inside handle breaks free from the rod the door will close but if the outside handle is stuck in the open position the door can't close.have you made sure the latch on the end of the door where it strikes the door post is not in the latched[closed ]position.the latch will be closed.if it is in the closed position and the door is open ,try opening the door using the outside handle.

http://www.canadiandriver.com/2007/02/14/auto-tech-frozen-cars-and-trucks.htm The latch may be frozen, see the link above.