I'm trying to delete the Ubuntu partition and then later I'm planning on running Ubuntu through VitualBox on Windows 7. The problem is I don't know which partition is Ubuntu so I can use that space for Windows.
Looking at your http://i.stack.imgur.com/lAY0n.png
If you used WUBI to install Ubuntu its contained in your C:/programs. Just delete it using 'programs add/delete' under Windows.
It would have not installed Ubuntu into a separate partition.
According to your partition table the only OS on that computer is the primary Windows OS.