Possible causes:
a) Bad optical drive,
b) Bad DVD disk
c) Not fully formatted hard drive
d) Bad hard drive.
Possible solutions:
1. Try Low Level formatting the Hard Drive
2. Try scanning the HD with Hard Disk Sentinel to determine it's condition.
3. Diagnose the optical drive installing another Windows, from a different burned Win 7 DVD, or from a different ISO. Try the installation Windows up to the point that 100% of the files are extracted. If 100% is reached, it was the disk.. if still the issue persists, it's possibly the Optical drive, or a possible Hard Disk issue.
4. Try installing from a USB pendrive.
HDD Low Level Format Tool 4.40...