After update (Win) problems, lag, black screen

Question

I have recently updated my Windows 10, and afterwards I keep getting black screen where only my pointer is shown and moves, NumLock works but otherwise the screen is black, previously (twice) it took a lot of time to be back to "normal" and show me the login screen after I tried pressing buttons etc. when I log on, the computer is almost unusable, very slow and slightest thing can cause it to crash/freeze and I have to hold the power button again, then when I turn it back on, it's black screen and the whole thing repeats.

If anyone has any idea how to fix the issue or the problem, I would greatly appreciate it.

P.S. The computer wasn't working very fast before the update but still very usable unlike now.

Thanks in advance!

UPDATE: In safe mode everything works fine.