an application was uninstalled by system account on a windows server 2008 machine. We did not do it. Looking the event viewer we did not learn anything more. How do I find out what happened.
Look for EventID: 11724
In case the program was uninstalled using Microsoft Installer you will find events from source "MsiInstaller".
I think that no other installer write events to Event Log. Maybe there will be some custom .log files from 3rd party un/installer.
Please explain the name and details of the software which was uninstalled. By that way i can tell you where to look for the logs or history of the software.