if the drive has been formatted with FAT32 rather than NTFS, then how to rectify it.
You could refomated to NTFS, right-click "My computer"->"management"->"storage"->"disk management"
and then right-click the partition you want to format, follow the wizard to complete the operation.
If there's some important data that you want be formated, you could use the command line:
click "start"->"run"->type "cmd" then it will pop-up the dos window. Then type the command line as "JasonAkkerman" mentioned.