OK, that's good
The first thing I would suggest is to read the following article a couple of times
1. If you understand the steps you can follow those to try Boot Repair. It is written for Ubuntu but should work with Lubuntu (I don't have a Lubuntu on board or I would try it).
If your Windows laptop has access to a Printer, you could print it first, or else after you choose the option "Try Lubuntu without installing", establish your internet connection, launch Firefox and follow the instructions "Live".
2. If that does not work, we can use the same install stick to start a process called "chroot" which is a little complicated.
I will be in and out a bit during my day, so if Step 1 fails, and given it is after 1:00 AM if you are in Denmark, I would try you with Step 2 when you are fresh. Actually, same really applies with Step 1 - your choice.