I was installing Windows 7 on my laptop the other day. It kept freezing at “Completing installation”.
After some Google research, I found the solution, which was pretty simple:
I was installing from a USB Drive, the solution was just to unplug the USB Drive.
So, if you have any USB devices plugged in during installation and system boot, make sure nothing is connected until you have a full boot into Windows 7. After you are in Windows, you can plug them in again and Windows will install the necessary drivers.
Hope it works :-)