Detecting application when run by another user. FindWindow or...?

[juliarg]

In my uninstaller, I want to handle correctly the situation when one user on the machine tries to uninstall the app when another user has it running. Normally, I identify the running application using FindWindow and then looking at the window's user data from GetWindowLong(). But in this case, it doesn't seem to work. Can FindWindow find another user's windows? Is there a better way to handle this task?