Hi ! After long time using BitDefender, i recognize that : I always get Blue Death of Screen when BitDefender updating if at that time i am using Process Explorer (and some programs of Sysinternal as Process Monitor, Autoruns ...) also if on my computer have installed PC Tools Spyware Doctor. I think driver of BitDefender (bdfdll.sys, bdfsdrv.sys ...) conflicted with a few drivers.
Crem 