====== How to Determine Existing Drive Letters in Windows ======

http://www.computerhope.com/issues/ch000854.htm

:!: These commands may require Windows Vista and newer versons of Windows.

===== Command Prompt =====

Using WMI:

<file>
wmic logicaldisk get name
</file>

or, even better:

<file>
wmic logicaldisk get caption,providername,drivetype,volumename
</file>

===== Powershell =====

Assuming you are on windows 7 or have installed Powershell:

<file>
gwmi win32_LogicalDisk -filter DriveType=4
</file>