Installing software during the login process is a generally bad idea, especially when users are not local admins (a GOOD THING!).
Software installation is an admin function, so approach it as such. I have a simple bat file that I use with our SWDIST product.. It is copied it to the user's workstation (C:\Temp), then a scheduled task is created using network credentials that are also a local admin (a DOMAIN\Computer Admins group). The BAT file maps a network drive to the install share and invokes an unattended installation directly from the share (NOT NetLogon!). Runs as admin, behind the scenes. No disruption to the user and no chance that the user can gain elevated rights.
With a deployment share and this batch file I can deploy to hundreds of systems a day.
Glenn
_________________________
Actually I
am a Rocket Scientist!