Not allowed to format the disk partition

[mucoool]

hi!
i got 3 partitions in my hard drive,out of which on 2 partitions i got windows installed ,and now i tried to uninstall the window from c drive,so i formatted the drive with dos .but it says;;;;;
ALL THe DATA WILL BE LOST!
proceed with format(y/n)y
then formatting starts and completes till 100 %
and then shows that
formatting the drive c is not allowed......
pls help me out.....

 

[aford10]

If you are inside windows, you can't format your windows installation.