Burn another DVD using ImgBurn at 4x speed. Where did you get the ISO?
First try running System Restore and System File Checker in Safe mode, or from the booted DVD Repair Console or Repair CD: System Restore SFC /SCANNOW Command - System File Checker SFC /SCANNOW : Run in Command Prompt at Boot
If this doesn't start it normally, boot into the DVD Repair console or Repair CD to run Startup Repair repeatedly. Startup Repair System Recovery Options
If this doesn't solve your issue(s) then from Safe Mode try some basic troubleshooting steps
to try to determine what the problem is.
If all else fails, you can copy out your files this way: Copy & Paste - in Windows Recovery Console
Then run your Factory Recovery partition or disks, or re-install windows 7