yours sounds like maybe you updated to a new kernel while having a
proprietary graphics driver in use, and didn’t also change the driver to
mesh with the new kernel…but that is just a wild guess, not based
on facts you have, but have not shared with us…
change that by adding some information, please:
what is your operating system and version?
are you using software from the Tumbleweed project?
what was/were updated, and from what source(s)?
if you choose the Failsafe option on the first green screen, will the
system boot to a graphical environment? if so, please show us the
terminal input/output from:
Probably the KDE session issue. To get around this: disable autologin, then in the login screen, select the “KDE Plasma Workspace” session and login. If autologin is disabled, something else is going on.