How to Mount a Hard Drive or Partition as a Folder in Windows 7
Information
This will show you how to mount an existing NTFS drive or partition as a VHD folder in Windows 7. By doing so, this will allow you to use a hard-drive as a normal folder on your main system drive.
This method comes in handy if you made your original system drive too small for your growing software needs or if you just want to be able to access multiple drives via one single drive letter.
Here's How:1. Create a new folder in 'Drive C' with an appropriate name.
2. Right click on Computer on Desktop or Start-Menu and click on Manage.
3. Click on Disk Management in the left hand pane.
4. Right click on the drive you wish to mount in the middle pane, and click on Change Drive Letter and Paths...
5. In the dialog that pops up click on the add... button.
6. In the new window that pops up click on Browse...
7. In this new dialog navigate to the new folder you created earlier.
8. Click on OK on all of the windows that opened during this tutorial.
This is how my drive space looked before...
This is how my drives free space looks now after installing Test Drive Unlimited which is 6Gb big to the location
C:\ProgramsEXT\TDU.
NOTE: Notice how the 6Gb has been added to my drive M instead of drive C.
Information
If you delete the newly created folder with stuff inside it, the 'virtual' folder is all you delete. any programs or data placed in seperate drives via this method remain in the other drives after deleting the folder.
Mount Drives or Partitions as a Folder 
It works for those still running both! 
