Asus P8Z68-V Pro

Trying to upgrade an old PC and now it won't boot. Made one minor setting change in BIOS to fix a problem installing windows and now it won't boot. I've tried removing the CMOS, replacing it, and removing various components of course. On boot, there are no beeps but the VGA LED is always red...

I have this board: ASUS P8Z68-V PRO https://www.asus.com/Motherboards/P8Z68V_PRO/specifications/ and this CPU: Intel Core i7-2600K Sandy Bridge 3.4GHz Right now it only has 8GB of memory and I need to upgrade the memory and maybe the CPU if possible. I found these two documents about...