Additional versions

6.3.9600.16384 (winblue_rtm.130821-1623)	5.35%
6.3.9600.16384 (winblue_rtm.130821-1623)	0.09%
6.3.9431.0 (winmain_bluemp.130615-1214)	0.28%
6.3.9431.0 (winmain_bluemp.130615-1214)	0.03%
6.2.9200.16384 (win8_rtm.120725-1247)	2.65%
6.2.9200.16384 (win8_rtm.120725-1247)	16.89%
6.2.8400.0 (winmain_win8rc.120518-1423)	0.09%
6.2.8400.0 (winmain_win8rc.120518-1423)	0.09%
6.2.8250.0 (winmain_win8beta.120217-1520)	0.03%
6.2.8102.0 (winmain_win8m3.110823-1455)	0.09%
6.1.7600.16385 (win7_rtm.090713-1255)	48.15%
6.1.7600.16385 (win7_rtm.090713-1255)	25.35%
6.1.7600.16385 (win7_rtm.090713-1255)	0.89%

This is a Windows system installed file with Windows File Protection (WFP) enabled.

acproxy.dll executes as a process with the local user's privileges. It is an auto-starting process that used the Windows Task Scheduler service to load when the user logs into Windows (sometimes this is required to bypass the UAC protection). The assembly utilizes the .NET run-time framework (which is required to be installed on the PC). This version is installed on Windows 8.