I had an issue where menu would come up but would not boot- i had to use that boot repair program to get it working- there’s probably other ways to fix it but I’m not real versed in linux so i went with the program- You’ll have to read the instructions carefully- print them out- as it can be a little confusing- but it worked well- Hopefully you can solve it by just reinstalling grub- that would be the easiest method, and you won’t have to have a separate program to do so-