clicking on more then one object or txt

I'm not to sure what happen but when I go to click on an object I'm not able to click on more than one. I'm using AutoCAD 2009.

Ex:

If I have five circles and I want to pick three it only highlights one at a time. When I go to select my second and third one it will unhighlight the first one(s) that I choose and just select the second one.

It never used to do this. I've tried looking at different settings, but I'm not sure where to look anymore. I know that I can hold the shift down and click on a bunch of different objects it will work, but I really dislike it.

Help Please.

Thank you!!!

Check your PICKADD system variable. It should be 1.

Oh perfect thanks so much. it worked!