virtualbox.org

Ok, this is my first time using VirtualBox and I am 100% sure I installed it correctly (the VM). However, when I start Ubuntu, it just says "GRUB loading."

What is the solution to this issue? Any help is welome! Thanks!

Not enough information to be able to help you.
Post the guests log file (as an attachment) and let us see what is going on.

Is this a problem just after being in windows? There are some windows software that writes hidden info into the boot sector and messes up grub.