I'm using Windows 7 and I've just purchased a new 3TB internal hard drive. I went to Computer Management to format the drive, but it will only allow me to access 2048GB. There is 746.52GB of unallocated space. When I right click on the larger part which I've formatted, "Extend Volume..." was greyed out. Please can someone tell me how to access all of the space on my new hard drive?