Here are some suggestions on what to try:
0. Before you even start, go into the BIOS and choose "Load Optimized Defaults" and then "Save & Exit". Reboot. Maybe this will even fix it, but if not, then at least you know where you started!
1. Shut down and open your case. Take a look at where everything is plugged in. Make sure all your connectors are tight. I also find that SATA cables can be touchy, so I often remove and reconnect them (from both the motherboard "end" and the hard drive "end"). Also, disconnect anything not essential to getting the computer up and running. This means, pull out that external sound card (if any), that wireless LAN card, disconnect any extra hard drives. Unplug all your USB devices except for a keyboard and mouse. You want basically 1 hard drive, 1 video card, 1 optical drive, 1 keyboard, and 1 mouse and that's it.
2. While you're in there, make a note of where your SATA drive is plugged in. Your board has two "sets" of SATA ports. Refer to the picture below:
3. Next, I'd enter the BIOS setup and start turning stuff off:
a. Go into
Standard CMOS features. If you don't have a floppy drive, set Drive A to disabled.
b. Go into
Advanced BIOS Features. Make sure your
Hard Disk Boot Priority is set to the appropriate device. Set the first boot device to CDROM (so we can boot to CD if we need) and the Second Boot Device to Hard Disk.
c. Set
Init Display First to PEG.
d. Go into
Integrated Peripherals. This is where we need to start turning stuff off.
e. If you aren't using the PATA interface at all (unlikely unless you have a newfangled SATA optical drive), you could go ahead and disable it in the BIOS. Even if you are using it for an optical drive, I'd probably try disabling it temporarily to see if you can get it to boot. So for now leave it alone, but later on try setting
On-Chip IDE Channel0 & 1 both to disabled. This is the setting to enable/disable your "old style" Parallel ATA IDE channels.
f. Set IDE/SATA RAID Function to Disabled, unless you are using a multi-disk RAID volume (in which case there are a bunch of other issues to address).
(continued soon)