Ok, this problem consists that when I boot my computer, and then GRUB shows up, I have these options:
(NOTE: My OS's are Windows 8, Ubuntu, Linux Mint and Pear 8 OS) (I asked this here since the main problem is caused by GRUB)
Linux Mint OS Boot Linux Mint OS Recovery Boot memtest x86 memtest x86 (I don't really remember what this boot option really said) Windows 8 (loader) /dev/sda1 < This one is bugged, when I press enter, it gets stuck on a blinking "-". Windows 8 (loader) /dev/sda2 Pear OS 8 8.0.0
When I select
Windows 8 (loader) /dev/sda2, it boots normally and sends me to the Windows 8 OS selection, Windows 8 and Ubuntu, when i hit Ubuntu it restarts my computer, it should send me to an Ubuntu GRUB (I think, cause it used to send me to a purple GRUB to boot Ubuntu), but it just sends me back as if nothing happened, anyways, long story short; I have deducted that Linux Mint is somehow bugging Ubuntu, because, since it's installation this started happened, I actually haven't tried uninstalling it to then boot Ubuntu but I have reinstalled it.
Summary: When I boot, then I click windows 8 loader, then I click Ubuntu, the computer restarts and goes back to the main GRUB screen instead of loading Ubuntu, making it impossible to access.
NOTE: I posted this on AskUbuntu and SuperUser since I don't really know where it goes, just please help me, I really need help with this D:.