Can't format partition


I am running dual boot with windows 7 and windows xp pro sp2. I am trying to format windows xp which is located in local disk (C:smile: but when I try to format it from windows 7 in Disk Management, an error comes up saying "Windows cannot format the system partition on this disk" and when I try formatting it from My Computer by right clicking on Local Disk C the menu comes up for formatting but once I click Start it says "Windows was unable to complete the format. I've also tried to do the Mark Partition as Active method from Disk Management but it's unable to be clicked. Any help here please?
"system" partition (DIsk Management flags) is "where all the boot files are (even W7's).
That's why it won't let you format it (the system would no longer be able to boot).
Use EasyBCD2.0 > "BCD Backup/Repair" > "Change boot drive"
Point it at W7 when it asks.
If W7 and XP are on different HDDs, change the BIOS to boot from W7.
Otherwise, reboot W7 and check Disk Management to see that W7 is now "active" "system" "boot".
XP will now be "ungreyed" and you can format it whenever you're ready.