Formatting my primary partition?

I am using windows 7, i am sorry if this is in the wrong section, i am a bit confused.

I have a dual boot pc, C drive has Windows XP, and E has windows seven.
I am a seven user, and i want to format my C drive.

When i go to disk management and try to format it says it cant format the C drive, C is the primary partition. Is there a way i can format my C drive, then install windows 7 on it?

Extra information:

Disk management:
http://dl.dropbox.com/u/53488115/disk%20management.PNG

Disk info:
http://dl.dropbox.com/u/53488115/Cmd.PNG

Yes you can but it will wipe out everything on the C drive. The reason you can't format it with Disk Management from inside either Win 7 or XP is because the current Win 7 boot files, and or XP files, are on that drive. Every version of Windows places files on the main, Disk 0 (C:\) drive no matter what other drive it is installed to.

The only way to format it is to boot from the Win 7 install DVD and during the new setup, or from a Command Prompt, you can re-partition and format the C drive. Or you can use a partitioning program to do it and then start the new install of Win 7.

Please have a look at this tutorial, which explains how to recover the disk space when Windows XP is removed from a dual-boot setup.

Partition : Recover Space Used by an Older OS

Your Win7 sees itself as E when booted because it was incorrectly installed from an OS and not by booting the installer.

I would clean reinstall to C if you prefer Win7 to be on C as it would be had you installed correctly by booting the installer.

If not then you need to convert E to Primary in order to mark it Active and then run Startup Repair - Run 3 Separate Times until Win7 starts and holds the System Active flags. You can then delete C and resize into that space or create a new partition there. Partition - Mark as Active
Partition Wizard Move/Resize Partition Video Help.
Partition or Volume - Create New

Note that to convert E you will also have to convert D as Logical drives must remain contiguous. How to set partition as Primary with partition manager?