How to fix Windows 8 boot loader?

Hello, I’m new to Linux and I seem to be having problems for every single step that I try to take into the whole understanding proccess.
At the moment, my biggest problem is that I’m trying to run Boot-repair in order to fix my windows 8 os.
But once i run it, all it does is to boot and to take me to the Ubuntu log-in screen in which i can’t even log in unless i choose to restart the system without running the boot-repair .
I really hope that someone can help me with this and with some other unanswered questions.

PS: I hope this is where i should’ve posted this and i havn’t messed up the topic category
PS2: please help :’(

When I use Boot-Repair, I do not use it in it’s own boot disk. Instead, I boot up with my ordinary Ubuntu live CD. Then, in the live session, I go to this web page:

https://help.ubuntu.com/community/Boot-Repair

On that page are the lines of code required to add Boot-Repair to your live-session repositories. I have copied them out for you here, for convenience. To add them, whilst in the live session, you’d need to open a terminal and enter the following lines of code:

sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair

Boot-Repair, should load automatically a few moments after you have entered your last line of code. If it does not, you should find it in the main system menu or, perhaps, the system-tools sub-menu. Or, you could type “boot-repair” in a terminal.

Once it’s opened, click the “Recommended repair” button.

Leave it to do its thing. It should take no more than a minute.

Once it’s completed, shut down and boot up back into your normal OS. You should now find your standard Grub menu with all of the available options.

It's giving me this error even if i have my USB connected.

You should run boot-repair from a live session, eg. the DVD or USB drive you used to install Ubuntu MATE. In the next version of Ubuntu MATE 16.04, you’ll be able to fix dual boot issues like this using boot-repair directly from the Welcome screen (live session only).

It can be considered dangerous attempting to modify the boot configuration on a system that is already running.

I renamed and moved the thread, since its in the wrong place and not a descriptive title for others to know what the problem is at a glance.

It doesn’t allow me to access the boot-repair while in a live session and i cannot connect to the internet either.
I can’t seem to find the available wireless connections.

Thanks a lot for the feedback, really apreciate it.

It will allow you to access Boot-Repair by adding, in a live session, the repositories I posted earlier and then following the rest of my instruction. If you do not have wireless internet in a live session, then you will need to connect your pc to your router via an ethernet cable. Then follow the instructions I posted and it should work.

Thanks for all the feedback, guys.
I couldn’t connect it through a cable but i upgraded to the last version of MATE and the problem fixed itself.