DiskPart is a handy command-line utility from Microsoft that lets you manage both internal and external storage devices on your PC. You can use it to easily remove write protection from a USB drive.

I know that if you have Hard Drive on Computer A protected, and take the drive out and hook it up via usb to Computer B you will be prompted for the password. Once you enter the password you can ...

In any case, it's possible to remove write protection from a USB drive. Some USB flash drives and hard drives come with a physical switch that lets you enable or disable write protection as needed.