That is not the error, that is telling you the location of where the log is that will tell you the error. In order to access that file youd need to follow the instructions to create a bootable ubuntu flash drive below.
In order to get your PC running again you may need to re-install windows. To do this download the Windows 10 Media Creation Tool off the Microsoft website and either make a bootable flash drive or burn a dvd to install windows 10. In order to get your files you either need to Take the hardrive out of your pc and put it in another and copy them off, or (this is fairly advanced I'd google it first before trying it) download an ubuntu iso, and create a bootable flash drive from it. Then boot from it and copy your files off your hard drive to another flash drive. Sadly you may not be able to get your files back if neither of those work for you.