Glad you got it working!!!
I assume the 1.5TB drive was reformatted in GPT. I had seen some mention (can't reference it though) where even smaller drives need to be GPT with Win 8. That's why I formatted my secondary 1TB with GPT. I have seen others have problems with resetting Secure Boot. Have also seen where resetting it after an install with it off results in a non-boot. I left it deactivated.
I wouldn't worry about not being to reset Secure Boot. You are no more unsafe than with Win 7. By now, the virus nuts have probably found a way around it anyway.
Here's a site that gives another way to enable Secure Boot; I haven't tried it: http://communities.intel.com/community/vproexpert/blog/2012/06/26/microsoft-windows-8--enabling-secure-boot