Possible Duplicate:
Why do I need restart computer after installing new software?
There are some applications that after its installation you must reboot your Windows in order to functioning. There are another ones (sometimes with the same functionality) that don't force you to reboot. I know that there are some applications that works with driver loading, so the system must be rebooted to makes the new application funcional. However I can't see for specific software features beyond this to force me to restart my system. So, my question is... What are the requirements or the features of an application that makes it a "must-reboot-application" after installation?