Where did you get Windows 7? If you burned the DVD, try burning another using ImgBurn at 4x speed.
Consider trying install from flash stick: USB Windows 7 Installation Key Drive
Make sure you have the latest BIOS version update, if so then reset the CMOS: Clear CMOS - 3 Ways to Clear the CMOS
Set the SATA controller in BIOS setup to AHCI first, then IDE if necessary.
Test your RAM with memtest86 CD scan for 5-6 passes. Remove all but 2gb of RAM to try install, swap RAM.
Test your HD using maker's full diag/repair CD scan: Hard Drive Diagnostics Tools and Utilities (Storage)