Return a Partition to Unallocated

I want to return a disk to the state it was delivered to me, or as close as I can easily get.
The disk has a small partition that I don't want to change.
The larger 'partition' was originally unallocated, but as XP wouldn't do a full format I did a quick format of that partition. I now wish to return the partition to its original 'unallocated' state.
How do I do this ?

Dumb_Question
11.Februay.2014

 

Disk Management is the Windows tool to do that.

Control Panel...
...Administrative Tools
...Computer Management
...Disk Management

then wait a few moments for the drive-table to be displayed.

 

mkdiskraw

 

Thanks for your answers, Christine and Adrynalyne

I've never heard of mkdiskraw, I assume it's a command line executable or something you run from Start>Run

As I have been using DiskManager, I used that, to be exact
Start> RClick My Computer (drop down menu) > Manage
from the left hand pane select Storage>Disk Management
New Right hand pane
From the bottom section of this I idenentified which disk I wanted, and Right Clicked on the partition I wanted to de-allocate, and from the drop down menu I chose 'Delete Partition' (left click on). The partition then displayed its size, and the word 'unallocated' which was just how I wanted it to appear. Sometimes you see the word Volume instead of Partition, it seems

Dumb_Question
11.February.2014

 

Take a look at post 2 and onwards if needed.

http://forums.majorgeeks.com/showthread.php?t=138098