Multiple instances of a program can easily be launched in Windows 7. If one instance of a program is already running then you can still start another by a simple Keyboard + Mouse click Combo.
You can simply hold down shift key while Right clicking to any application i.e. Combo of Shift key & Mouse Click and new instance of that application would be launched .
Notice number of instances has increased of Internet Explorer, Windows Explorer, Paint, and Live Writer after Shift + Right Clicking them.
"Windows 7 Tips: Launch multiple instances an Application "
Reference : www.WindowsVJ.com