I have the following problem:
I have 2 hard disks on my pc. My first disk is a 500 GB hd and I have got Ubuntu 12.04 installed a long time now. My second disk is a 2TB disk in which I just installed windows 7 x64.
Everything was just fine, but 3 days ago I installed SAPPHIRE HD 7770 GHz Edition OC 1GB GDDR5 in my system. GRUB menu (which I tweaked through this post : I can't get grub menu to show up during boot ) after the installation of the new graphics card boots normally into Windows but it will not boot under any circumnstances on my Ubuntu 12.04 ('Check signal cable message') . I even tried with a live cd it just went to black screen again 5 seconds after it had started.
I have got some serious projects on my Ubuntu since it is the primary OS that I am using so a little help would be much appreciated.
My system: ASUS motherboard 2 hard drives just I mentioned, my new graphics card SAPPHIRE HD 7770 GHz Edition OC 1GB GDDR5, RAM: 2 X 4 GB , processor : AMD A4 3400 CPU with embedded graphics card(that I am not using anymore).
PS: Note that it worked well up until 4 days ago, without the new graphics card.
Please help me if you can. Thanks in advance.