Replace Windows with Opensuse on a dual-booted device
Boot from Opensuse live cd, do a os-prober in terminal to see if all operating systems are listed.
If yes, then you are safe. Just select manual partitioning scheme,then select the windows partition, format it and install Opensuse there. Install the bootloader in the harddrive, not in any partition.
if it doesn't detect any 1 operating system, then there is a conflict in UEFI/EFI/Legacy bootloader. Probably opensuse is reading the UEFI BIOS, while previous operating systems are installed in LEGACY bios. A Simple solution to this problem is to just turnoff the UEFI bios & then simply follow step 1.
Enjoy :)