Systems Management

I´ve got a question.

I want to install the reader 7 and the updates per gpo, so I made a gpo, with the 4 msi packages. I tested this with 4 gpos, and now I made 1 gpo, with the 4 packages to install in a row (7.0, 7.01, 7.02, 7.03), the function "update" didn´t work, unfortunately, or I made something wrong :-) I´m new to this stuff. (gpo & softwaredeployment)

Now I tested it on my testmachine, and it worked.
so I uninstalled the update 7.03, and restarted the testmachine, but the update is not installed anymore::::::
I thought, that on every systemstart, it will be checked if the software is installed or not, and if not it will be reinstalled.
Is this so?