Hi everyone, I am new to this site. My problem starts with installing Win7-64 bit on my Toshiba Satellite laptop, U845W-S400, 500 hdd/sdd, 4Ram. Originally it has a pre-installed Win7 premium, I have formatted the laptop and tried to install Win7 ultimate but did not work, after headache I have temporally decided to install Win8.1, it worked well. I have tried again to install Win-7 64bit ultimate by booting and adjusting the Bois setting from csm to UEFi boot, booted fine and while win7 installation in progress no drivers were identified (you cannot see any drivers). As recommended I have copied SATA drivers to the USB and when tried to load them through the installation process it gives an error and not identified. Secondly, I have tried to install win 7 by logging onto the pre-installed win8.1, it went fine and copeid win7 files but after auto restart through win installation it gave the blue dead screen and failed. I have gone through these for many weeks and went through so many sites amongst is Toshiba sites and so many YouTube videos but no success. I would appreciate it very much if someone could suggest a solution.