I am having some problems with the hard drive in my Samsung laptop, and it needs to be replaced. I have the replacement drive, and after installing it, and making sure that it is connected properly, it is not being recognized in the BIOS. Actually, there are no options to choose from under the boot section. In the past, I remember installing an HDD on a tower of mine, and the drive was not recognized either, but then when I loaded the OS installation disk, the drive was picked up. The Samsung laptop is currently running Windows 8.1, but I have Windows 7 on a flash drive that I am hoping to install on the new drive. I am not able to do what was done in the past, and just load the installation media because the flash drive is not being recognized either. I am positive that both the flash, and hard drive are in fully functional working condition. If I disable secure boot, I am able to boot from a CD/DVD, but the flash drive is still not being picked up. I have tried several different flash drives, with no success, and if I place the hard drive that has Windows 8.1 installed back in the system, it will boot up like it normally would. Can someone please help me solve this problem? Thank you for your time.