I wanted to try ubuntu on my laptop without installing it, so I thought that installing the “ubuntu CD boot helper” would be useful; I installed it on windows 8 and, after that, everytime I turned the computer on, I got a *blue screen asking me to choose ubuntu or windows; with the ubuntu live CD inserted, I picked the option 'ubuntu' on the blue screen, but the CD never booted using this method, I just got an *error message. I didn't try to get rid of this blue screen and the error coz I thought it would be replaced by GRUB2 after the instalation of Ubuntu.
I then created a Ubuntu live USB (14.04) and installed ubuntu following all the steps on this tutorial (http://itsfoss.com/install-ubuntu-1404-dual-boot-mode-windows-8-81-uefi/), but nothing worked; Grub didnt appear, I then was provided with a *black screen (the windows boot manager) that asked me to choose between ubuntu and windows, and got the same error message after picking the ubuntu option (btw this windows boot manager appeared everytime i turned the computer on). Reading the comments on that tutorial, I found out that, during the instalation of ubuntu, I picked the wrong device for the boot loader; making some research I found out that, if there is an EFI partition, the boot loader have to be placed there.
So I used the windows disk management to erase the partitions created for ubuntu, left the space unallocated and installed ubuntu all over again, this time placing the boot loader in the EFI partition. Now Grub works well, I can boot on both operating systems when I need them. The problem is that, unlike I thought, the Grub didnt replace the windows 8 boot manager, they now coexist; in the Grub options, there are the following:
-Advanced options for ubuntu
-Windows boot manager
Whenever I want to use windows I have to choose the option "windows boot manager", it then shows the black screen with options for Ubuntu and Windows, and only after picking this option I can access windows. So I want to know how can I get rid of that annoying windows boot manager (if its any possible at all?!) or add an entry on Grub so I can boot on Windows directly when necessary (replace "windows boot manager" option for a "windows" option).
*my screens mentioned here, with equivalents in english (I cant post pictures or more than 2 links since I dont have 10 points reputation): https://drive.google.com/folderview?id=0B0CB6GipDaHZMXlMN0F2SEpGU3c&usp=sharing