Where did you get Windows 7? Did you burn a DVD yourself? If so confirm ISO source and burn to DVD using ImgBUrn at 4x speed.
Unplug all other HD's and peripherals to try install.
Enter BIOS setup to reset to defaults: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS
Test your RAM and HD: You can burn to CD or write to flash stick Hiren’s BootCD
to boot to test the HD with the maker's diagnostics, Check File System after making a full disk partition with Partition Wizard, test your RAM with memtest86.