I first installed the Ubuntu. Then I partitioned my hard drive and I installed the Pear. Finally the last operating system that I wanted to install was Windows 8, so I did so. However now that I installed the Windows 8 there is no grub screen or any boot screen it just goes straight to Windows 8. Is there a way to somehow fix this... because it's like I don't have any other operating systems on my computer now... I'm not sure what to do.