How to disable & enable usb port or usb detection from your computer

In This I will tell you how to disable usb port or usb detection from your computer. firstly for knowing this you have to familiar with Windows registry because if you are not familier with windows registry you can do this but you won't be able to understand that how it works actually. So before starting this I will tell you about windows registry in breif. Have u ever thought how some viruses effects your computer and makes it slower how some viruses disable your task manager and sometimes how they disable your explorer exe ,If no then you have to know that its all the game of windows registry .Actually windows registry is a Hierarchical database of windows which holds all the information about windows either it is related to windows icons or it is related to windows internel features like user accounts,task manager , In-fact when you install a new software in your computer each and every information related to that software also stores in windows registry like serial keys installation date etc.  So now we start the process of disable & enable usb port from your computer for this what you have to do just goto
run prompt type REGEDIT it will open windows registry then goto 
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\USBSTOR
and look for start a 32-bit dword value then open that dword value & change it from 3 to 4 like in the below image when you do this your usb devices will not be detected by windows means when a user connect an usb device it will not show.

For enable it just change the value of start again to 3.So now i think you've understood the process of enable and disable usb detection from your computer but might be 1 question can strike in your mind

that is why 4 we use to disble usb rather we can use 1,2,5,6 etc. So I tell you what is the reason behind it.  100 is the birary value of 4 (you can check it by dividing it with 2 and arrange the reminders from bottom to top) and this value is the value which uses to block USB and similarly 011 that is the binary value of 3 which is the default value of detecting USB by windows.So now you've understood How to disable & enable usb port or usb detection from your computer and also you've know how it works actually so do it and enjoy but be carefull if you don't know any thing in windows registry be away from it coz a littile bit change in windows registry may be very harmful for your computer means if you don't know about the reaction of changing any value in windows registry don't do it.