dual boot win10 and suse leap screen resolution

running win10 upgrade, tried install opensuse leap…partitions were dos…soooo i deleted windozes, wiped hdd. had a full win10 pro iso and re-installed. now i have uefi. installed opensuse really quite painless and fast…looks good except everything is barely readable,too small on my 16x9 hdtv…resized icons and fonts but not all gets changed. so i changed resolution settings to an unsupported resolution…black screen, reboot, black screen, unable to do anything now…question how to get up and running again? and how to change resolution safely …also is there an onscreen keyboard available, greatest thing it is. sit back on couch feet up with just mouse and pad…ah so handy…
as stated previously leap runs very good so far…I’m running an nvidia 950, very strong up to date vid card…thanks

IMO your current situation doesn’t have easy answers because support screen resolutions are a result of both the monitor you’re using and the display driver you’re using.

Undoubtedly the first thing you should try to do is to boot to Rescue Mode…
When you boot and arrive at your GRUB screen, you should click on “Advanced” which will display your installed kernels as pairs…
I describe the following only because the default GRUB screen isn’t wide enough to display each entry in its entirely, so you should know the following…
(BTW - If you want to fix this craziness in not being able to see the entire entry, I wrote some scripts that fix this easily at the following link, I’ll probably create LEAP versions this week but you can modify the 13.2 to work with LEAP without issue (or wait for the new scripts))

The first in each pair is the “boot with normal settings” which you would select only when everything is fine.
The second in each pair is the “Resue mode” which is what you want (choose any, or from the first pair which would be the latest)

With any luck,
That second selection will enable you to see your Graphical Desktop, and then you can go in and modify your screen resolution settings properly (if you can remember what they were).
Probably the alternative is to install if necessary and use xrandr. When I’m running IceWM, I install Arandr for a graphical tool to change resolution.