First, check if you are booting in Legacy or UEFI with Windows. Mixed can be done, but it is not always easy nor the best way.
It would be less problem to make certain both Windows and openSUSE are installed in the same, that is, both Legacy or both UEFI.
Also, more precision is required in your information, although I think I know your layout, but guessing can be hazardous.
So, boot with the installer, go to the Rescue system.
In there, get the output for:
fdisk -l
That is a lowercase L, not a numeral one.
and the output for:
parted -l
Please copy and paste the output to a file so that you can copy and paste that to this forum. Include the command as given along with the corresponding output.
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Oh. How to get the output from the Rescue terminal to a file? Easiest is if you can plug in a USB key. You would simply mount that key with:
mount /dev/sdXN /mnt
You can find out what the true letter and number for that device would be using either of the above commands.
Once mounted, run the above commands but add a redirect to a file on the device you just mounted, as follows:
fdisk -l > /mnt/fdiskoutputfile
parted -l > /mnt/partedoutputfile
If you had a Linux partition on the HD, you could have mounted and used that instead, but I think you only have Windows partitions, AFAICS.
That output is needed. Only then can we really begin to help you.
