When you get problems with installing Windows 7 the first thing that you should check is the memory. The hard drive is probably ok as you are not getting a SMART error and the media is probably ok if you don’t get a read error and the media is genuine Microsoft. I would check your computer with a memory test program such as memtest86 or at a pinch the memory test program on the Windows 7 installation disc. Windows 7 is very critical of the memory and the slightest problem will result in the kinds of problems you are having.
You said that you checked the memory, how? Did you run the test for long enough? Try installing Windows with only one stick of memory fitted.