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Windows 7: Unable to format C drive

21 Mar 2012   #1

Windows 7 Ultimate 32 bit
Unable to format C drive

Actually previously I was having Win7 Starter on my laptop which was installed on C drive, but somehow it got infected by virus which I was unable to remove. So I tried to install new OS on C drive but I was unable to do so. Then I tried to install new OS on the drive other than C and installed. But now I'm unable to format the C drive in which previous OS was there. Whenever I try to format C drive it is showing message window like this, "Windows cannot format this drive. Quit any disk utilities or other programs that are using this drive, and make sure that no window is displaying the contents of the drive. Then try formatting again". I think old OS is still there. How can I remove the old OS from C drive? Please suggest!

Attached Images
Unable to format C drive-untitled.png 
My System SpecsSystem Spec
21 Mar 2012   #2

Windows 8.1 Pro RTM x64

By convention, the C drive contains the currently running Windows OS. As such, it is not possible to format or delete this drive/partition from within Windows itself. It is typically formatted during the OS installation.

If you have managed to install the OS on another drive/partition (which you say you have), you should be able to delete/format this partition. Just check which letter has been assigned to it (which won't be C, as this is reserved for the currently running OS).
My System SpecsSystem Spec
21 Mar 2012   #3

Windows 7 Ultimate 32 bit
A drive

Thank u Mr. Dwarf.
The newly installed OS is on "A" drive.
My System SpecsSystem Spec

21 Mar 2012   #4

Microsoft Community Contributor Award Recipient

Microsoft Windows 10 Pro Insider Preview 64-bit

Hi Shiva :)

You may try it using the Partition Wizard Bootable CD .
My System SpecsSystem Spec
21 Mar 2012   #5

Windows 7 Pro x64 Windows 10 Pro x64

You should reinstall, delete all partitions then click next. Never name your partition A:

You are booting from the dvd yes ?

Gregrocker has a link for a perfect install.
My System SpecsSystem Spec
21 Mar 2012   #6
Microsoft MVP


On many new HP's the Recovery partition will still run from it's hotkey even after a clean reinstall to C. You can try that now by tapping the F11 key at boot, or booting the Recovery Disks if you made them first.

If HP Recovery will not run then you don't need any partitions on the HD now. I would wipe the HD first to get the cleanest start, using Diskpart Clean Command from the DVD accessing DISKPART At PC Startup.

Then follow these steps to get a perfect Clean Reinstall - Factory OEM Windows 7.
My System SpecsSystem Spec

 Unable to format C drive

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