Hi guys,
this morning i’ve tried to updated opensuse leap 15 but at the end of this an error message appear on terminal. After that i was unable to run yast, some program are deleted, i was unable to open folders by clicking on that but the big problem is that after a force shut down (from the keyboard button) the system won’t start. Someone can help me with out making me reinstall all from the crave? Thanks a lot for the helpp 
Not enough relevant information here in order to help using other methods, but I would suggest the best option would be for you to use the DVD installer and choose the Upgrade option.
This will fix your current installation to the version on the DVD without removing or changing the programs and utilities you currently have installed and without losing your personal data.
After it is upgraded, connect to the internet and run the updates again.
Best way to do that, I suggest, would be first disable all Repos except the Main operating system Repos (4 of them), then open a terminal, change to root with
su -
(note the minus sign in the above command)
then update with
zypper up
When the update is done, post your Repo list here (between quote tags, use the “#” icon in the editor menu above the forum messaging window, middle row, third icon from right), which you can get using the following command:
zypper lr -d
for further assistance.
I suspect you may have an additional repo enabled that might have caused your problem in the first place.
First: No filesystem likes forced reboots.
Second: Take notes of error messages, photographs or whatever
Third: Can you still boot from an install stick ? Asking this because we could use that to get your computer running, then attempt to repair what was damaged.