trustedinstaller.exe in vista

Trustedinstaller.exe was activated when I started wmplayer and realplayer together. After that, trustedinstaller.exe kept appearing and I couldn't play any DVD using wmplayer. After I uninstalled realplayer, restarted my computer and run wmplayer, trustedinstaller.exe was activated again. I decided to wait till it finishes using my resources then play a dvd. TrustedInstaller.exe disappeared soon after. :)