The only time I ever got a blue screen on Win7 was from the new WAS Driver (lol and I was the one that suggested having a WAS driver).
But it may be what you have BB set to like the Audio Driver or the default Synth etc. There's some ini files you can delete that have the setting in so it will default back to factory but at the moment I can't remember exactly but look at the latest date files in C:\bb\Preferences

https://www.pgmusic.com/techfaq55.htm#93