GNU GRUB 2.0

[Uden Beater]

Guys I need help. Earlier this year I made my laptop a dual-boot system, Window 8.1 and Backbox. Later I got bored with Backbox and delete it's partition from my hard drive. After that, I try to recover Window Bootloader using recovery media and it didn't work. I try another solution, using Ubuntu-Live trying to remove ext4 partition. It say it already remove and when I reboot my laptop, GNU GRUB 2.0 still there. Any solution?

[2FA]

Use a Liveboot USB and mount the partition that holds the bootloaders. You should see a folder called Grub or something similar along with another that says Windows. (I'm not of the exact naming since I did this quite a while ago) Delete the directory called grub.

[Uden Beater]

Already delete the ext4 in Ubuntu but the problem still happening

[Kiyuubi]

Just put in a Windows bootable media and repair the startup.  The automatic should work just fine.  If it doesn't, then open the command prompt in there and type

bootrec.exe /fixmbr
bootrec.exe /fixboot
bootrec.exe /rebuildbcd

 

 

[Uden Beater]

I already try 

bootrec.exe /fixmbr

But it didn't work. I will try using the other 2

[Sauron]

Grub doesn't install to the partition of the os. Rather, it installs to the drive itself. Simply deleting your partition was a very bad idea, because you lost grub's configuration files. If recovering the windows boot loader doesn't work, try backing up your windows partition, then reinstalling windows (formatting the whole drive) and copying the backup over the new main partition. This way, windows will have created a new functioning boot partition and you should be able to boot in your os.