First time login (local or domain) takes over 1 min 10 sec after installing Symantec Management Agent

Hello,

We are running CMS 7.1 SP2 and Windows 7 x 64 bit (Dell Optiplex 790), and first time login takes over a minute  showing  "preparing your desktop". Uninstalling the Altiris Agent brings that time down to 11 sec. Both local and domain accounts are affected. The PCs are in a student lab environment, so in most cases people would log in to a computer that they haven't logged on before, so it is quite annoying. Has anyone come across this before? Do you have any suggestions on what logs to check for more information?

Thanks!