When I was in college, many times I needed to disable system's USB port so that nobody other than me can use that port. So what I was doing is simply editing registry editor for USB port everytime. When I had to use it, I was enabling it else I would be keeping it inactive and would rather say to my friends that "buddy! USB port has some problem in my system :(" 

I know you might have seen such a common topic here there always but whats the harm in keeping such stuffs in our site too! So I shared it here (may be little bit late, but i am sure it will still help many people from our blog :))
Now the trick lies here in registry editor USBSTOR keyword which is under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services To disable the access to USB port, in Vista/Windows XP and 2000, follow the steps below  (I have not tested it on Win 7. Please someone verify it and let us know)

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate, and then click the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR
4. In the right pane, double-click Start.
5. In the Value data box, type 4 (REG_DWORD), click Hexadecimal (if it is not already selected), and then click OK. 6. Quit Registry Editor.

To re-enable a disabled port, follow these steps below:
1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate, and then click the following registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR
4. In the right pane, double-click Start.
5. In the Value data box, type 3, click Hexadecimal (if it is not already selected), and then click OK.
6. Quit Registry Editor. Or else If you are lazy person like me 🙂 then just save two different .reg files one for enabling and other for disabling purpose.

Steps To make one click working for enbaleUSB:
1. Open Your favorite editor or simply notepad
2. Type these lines there: REGEDIT4 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR] "Start"="3"
3. Save it as enableUSB.reg (You could save it as anything but for our comfortness I wrote like that. extension should be .reg anyhow)

In the same way to disable USB port follow these steps:
1. Open Your favorite editor or simply notepad
2. Type these lines there: REGEDIT4 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR] "Start"="4"
3.Save it as disableUSB.reg