It's my first post here.

So the situation is this:

I have bought N56VM, which was full of bloatware, of course. So first thing I decided to do, was to install Ubuntu for dual booting(normaly, I am not a Linux user. just decided that it's the time to make a switch). It proved to be quite a challenge. I knew nothing about UEFI and such. But after extensive searching and help from friends I have managed to do it.
Both OS were booting then.
Then I decided to flash the BIOS from 206 to 214(LINK ). (I had no idea that "Disable CSM when SecureBoot is enable" had something to do with UEFI, thus making Ubuntu unloadable, but I have found it out only after failing to Re-Install Win7)

Next, I decided to do a clean Win7 installation. I have formatted the C drive, and the recovery partition(we all need the extra space, don't we?).

And that's when I have realised that something is wrong. After formatting C drive, I realised that I cannot install Win7 on it.
I get an error saying Windows cannot be installed to this disk. The selected disk is of the GPT partition style.here's a pic:
http://imgur.com/5vj3xcM

there is an option of Load Driver. but I have no idea what driver are they talking about, and it's not on the Win7 install disk.

I do not have any important files in Ubuntu distro.

The questions:
Is there a way to keep the current BIOS version and be dual-booting Ubuntu alongside Win7?Is there a way of turning off the secure boot? i can't find it in the bios. here are the pics:
http://imgur.com/a/ar1IZ#0
http://imgur.com/9TyHdyh

if not, can I safely flash BIOS back to 206?

What do I do to install Win7 back on this machine?
I was thinking of wipping the whole HDD, and then hoping that I can do a clean install of Windows without the hassle.

What's the best course of action?