Follows are some indications that are common symptoms of getting infected with Trojan horse.
Opening and closing of CD/DVD-ROM
Computer screen blinks, turns upside down, changes resolution.
Wallpaper changes automatically.
Disable of task manager.
Task bar disappears for while.
Sudden opening of web pages.
Change in data and time of system.
Right click and left click swaps their functions.
Freezing of mouse and keyboard.
Auto movement of mouse pointer.
Playing of music even though you haven’t turned on any music player.
Mouse pointer disappears.
Unusual restart and shutdown of PC.
Unwanted software installation.
Disable of Anti-Virus and Firewall.
Change in screen saver.
Disappear of task manager, tray icons, quick launch, start button and desktop icons.
Fluctuation in screen light intensity and volume.
Changing of screen savers.
Others receiving emails from you which aren’t sent by you.