Welcome to the forums
exact model and number please?, when was the last time it booted OK?, what changes have you made since it last booted clean?, do you have Timeshift or similar installed?
As a suggestion, try help.ubuntu.com before asking for help in a general linux forum.
It's not that members here do not want to help, but that one should always try to find the answer hisself first.
I used help.ubuntu.com a lot when learning Linux for the first time using ubuntu.