Sophos Control Centre can deploy Sophos antivirus software to your client computers remotely.

In my experience installation on Windows XP never caused any issues and machines were ready out of the box. On Windows 7, however, installation was failing with folowing error:

0000002e  The installation did not start.  The computer may have been shut down, renamed or disconnected, or a required service may not be running.  It may be running Windows XP Home or Windows Vista

All I had to do to make remote installation work on Windows 7, was to launch the Remote Registry service and set it to start automatically.

If this doesn’t help in your particular situation, try following Sophos articles:

http://www.sophos.com/support/knowledgebase/article/29287.html
http://www.sophos.com/support/knowledgebase/article/29728.html