Reset the BIOS to defaults: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS
While in BIOS setup set SATA controller to AHCI to try install. Make sure the settings for changing back to your onboard display are correct.
Next wipe the HD with Diskpart Clean Command
from DVD accessing DISKPART At PC Startup
Unplug all other HD's and peripherals. Remove the video card completely, then check that it didn't damage the mobo.
Download the latest official installer ISO for your licensed version and burn to DVD with tool provided here, then follow these steps to get a perfect Clean Reinstall - Factory OEM Windows 7.
Next write the ISO to flash stick, physically unplug the DVD drive to boot the flash stick for install using one-time BIOS Boot menu key under USB, REmovable or HD's. Set HD itself as first to boot in BIOS setup.
Test your RAM, swap sticks, try install, swap sticks again.
Test your HD using maker's HD Diagnostic
extended CD scan, then wipe the HD with that tool or using Diskpart Clean Command
from installer using DISKPART At PC Startup
Report back results of all steps.