Well, if your other stuff is running fine, it's most likely some kind of software issue. Your hardware is bog standard stuff that thousands of people are playing the game with and having no problems.

I assume that even after your formats, you installed various drivers and ran Windows Update. It just so happens that a couple weeks back, a windows update ( kb 2859537 ) was released that caused crashes similar to what you're experiencing to some people.

Try turning off Windows Update, then using system restore to undo the Windows Updates that have been installed. Then just install the drivers you need for the game and see if it's still crashing.