Nasm - "real" randomness via uninitialized variables?

I'm trying to build a number generator in Nasm. For this purpose I'd like to declare a few "variables" (I know Nasm only has labels, not variables) but not define them. The problem is when declaring variables in .bss they are automatically null initialized. My Question is: Is there a way to let the variables keep the values their reserved memory had, before it gets null initialized?

The OS is windows.