What I did to get in this mess
I'm a new ubuntu convert and tried dual booting my lenovo ideapad 100 with Ubuntu gnome and windows 10. Turns out i failed, I installed ubuntu in legacy mode because that was the only way the laptop would let me. I didn't delete my windows partitions but windows 10 can't boot now, I guess I will need to reinstall it in legacy mode (How do I do that? Being able to use my old partitions would be great too).
Installing ubuntu from 32 bit to 64 bit
Another problem I have is that I installed the ubuntu GNOME 32 bit version, thinking I couldn't use the 64 bit version called AMD64, because i have an intel processor( Only later did I realize that i can, and should've installed that). So I looked around and found that I can somehow upgrade it in the terminal, but that reinstalling it completely is better and less hassle. This being an almost clean install I don't mind reinstalling, but how am I supposed to do that? ( + I've already flashed the needed 64 bit image on a USB)
Additional
Here's my boot info if that helps: http://paste2.org/A0ZX9f7m