You may need to reflash your BIOS if it is not responding to changes. But try to repair Windows 7 first as BIOS is safest flashed from Windows.
Try booting the DVD using the one-time BIOS Boot Menu given on first boot screen or in your Manual. I believe it's ESC key on Evga boards.
If this fails, double-check you are following the steps to correctly set DVD drive to boot first in BIOS: http://pcsupport.about.com/od/tipstr.../bootcddvd.htm
If this fails, test your memory using memtest86 CD
for 5-6 passes or overnight, then your HD using maker's full diag/repair CD scan: Hard Drive Diagnostics Tools and Utilities (Storage) - TACKtech Corp.
Next it may be necessary to reflash your BIOS with the lastest BIOS version from USB flash stick or CD.