I formatted my laptop's Windows loader partition (ext4) while installing Ubuntu 15.04, and when I tried reinstalling Windows, it can't find any drives.
I already formatted the Linux drive into NTFS with gparted, and I have another NTFS partition in my computer, yet still, my Windows 8 setup cannot find a single parition for me to install it on.
PS: The Linux installation failed with
Executing 'grub-install /dev/sda' failed. this is a fatal error
and now I can't do anything.