NOTE:- This will DELETE all your data from the hard disk. whole hard disk will be ERASED. Take backup of ur files to an external drive before u proceed. \\\Follow this link to Take backup from the hard disk without logged in to the system.(if u can't logged in to ur system b'coz of some problem)///- Turn off the PC, and put in the Windows installation DVD or USB key.
- Boot the PC to the DVD or USB key in UEFI mode (change in BIOS ).
- From inside Windows Setup, press Shift+F10 to open a command prompt window.
- Open the diskpart tool: type and enter as below
diskpart
- Identify the drive to reformat: type and enter as below
list disk
- Select the drive, and reformat it: type and enter as below ( one by one )
select disk <disk number> ///eg:- select disk 0
clean
convert gpt
exit - Close the command prompt window.
- Continue the Windows Setup installation.
- When choosing an installation type, select Custom. The drive will appear as a single area of unallocated space.
- Select the unallocated space and click Next. Windows begins the installation.
//source: technet
