Install Altiris agent 7.1 failed

I have try install Altiris agent on on of workstation many times, but it failed on, when I try to double click AexAgentActive.exe file, is show:

AexClientActive

   Please ensure the Altiris Agent service is running before attempting to active the UI.

so I checked the services, I did not see the Symantec Management Agent service exist.

I even manually removed agent from the registry key, I found the article from your web site tell me step by step how to remove altiris agent, then I shutdown the machine, then manually install from URL:

\\altirisserver\altiris\ns\agent\altirisagentdownload.aspx,

still not working, what should I do?