I kept tapping the F8 key (although this may be different for other manufacturer's computers) and came to the screen which show the Safe Mode, Safe Mode with Networking, etc. Then chose the first option which is Repair your system, and then choose the Command Prompt option and typed in format c:
You'll notice you'll be at the X:\windows\system32 directory.
You'll have to do a dir /p switch and choose directories D: or E:., then do a dir /p to locate the actual partition where it's installed. now switch back to the X:windows\system32 and type format (name of drive)
In other words if you windows partition is located in D:, you would type format D: and hit enter.
NOTE: Make sure you have the proper drive where windows 7 was installed