Remove Hidden EISA Recovery/Diagnostic Partition
<http://tinyurl.com/RemoveHiddenPartition>
Excerpted from My Digital Life article at the link above

[Dale Note: When upgrading from Vista to Win7, often the Vista system has a large special Recovery partition. Once upgraded to Win7, this hard drive space is wasted. But it's hard to remove, and to give that space to the C Drive. Here's how I did it. Note that it can be done in Vista before the upgrade or in Win7 after the upgrade.]

Here’s the trick to delete and remove the EISA recovery or diagnostic partition in Vista. Before proceeding with the deletion action, make sure that at least a set of Recovery Disc Media has been created. Else, you won’t be able to restore your computer to working and factory default condition when any problem on PC requires reinstallation.

1. Open a command prompt as administrator.
2. Run Diskpart application by typing Diskpart in the command prompt.
3. In the “Diskpart” prompt, enter rescan command and press Enter key to re-scan all partitions, volumes and drives available.
4. Then type in list disk and press Enter key to show all hard disk drive available.
5. Select the disk that contains the partition you want to remove. Normally, with just 1 hard disk, it will be disk 0. So the command will be:

   select disk 0

   Finish by Enter key.

6. Type list partition and press Enter key to show all available and created partition in the disk selected.
7. Select the partition that wanted to be deleted by using the following command, followed by Enter key:

   select partition x

   where x is the number of the EISA based recovery partition to be removed and unlocked its space. Be careful with the number of this partition, as wrong number may get data wipes off.

8. Finally, type in delete partition override and press Enter key.

Once the partition has been deleted, exit from Diskpart, and now users can use the much familiar and much easier Disk Management tool in Windows (diskmgmt.msc) to manipulate the freed unallocated partition. Users can create a new volume (partition) with this space, or simply merge it to existing partition by extending the size of the existing partition.

Copyright © 2005 - 2009 My Digital Life

[Dale Note: At this point, boot back into Vista or Win7 and go to Disk Management. It's deep down in Control Panel, so the easiest way to directly there is to enter diskmgmt.msc into the Search Box. Once there, right-click on the C Drive to get a menu. Choose the "Extend" option and follow the prompts to make the C Drive use the complete hard drive capacity.]

(Win7&Vista_RmvHiddenPartition.htm)