Where did you get the iso file from ? How did you burn the DVD ?
Did you burn at slow x4 speed ?
Any Over Clocking of ram or cpu ?
32 bit or 64 bit CPU & Windows 7 ?
Which of the 2 HD's are you trying to install to ?
You might try with just 2gb of RAM, this has been a know problem in the past.
Also disconnect any extra peripherials that are not needed for the install right now.
They can be connected later & recognized by Windows 7 at that time.
This is just a starting point. " Doc "