Windows7 how to format C disk?

I used to use the XP installed in the C-disk, is the FAT32 format and now installed a Windows7 system in E disk now I want to put the C-grid of the Windows7 installed in C, but I have deleted Windows XP later found that the lattice can not ... But now I can't put Windows7 in C.

There is a Windows 7 installation tool and the same as a CD-ROM installation to extract the mirror to D disk or D disk root directory and then run the Windows 7 Installation tool Restart the computer into the installation interface format C and then choose to install to the C disk and the CD-ROM installation exactly the same you need tools to send you

And you're not going to reinstall the system. C-Grid, you're not going to get in Windows 7. Windows 7 boot files more on main disk C disk D-E disk how many logical disks

You have 2 choices right now.

First, reinstall the system grid C disk to install the system C disk;

Second, keep the C-disk to maintain the current-like XP system download.