EXS 24 Logic Sampler Users Group

I need to know why my hard disk of my pc which is 20gb is
split into 2 sections of each 10 gb!
Why is that,what's the use?
Now i'm into buying sample cd's i'm gonna need all the hd space
possible. I filled the first 10 gb section to the brim,
how do i access the second section of 10 gb. The first section
is simply station c:, but i cannot find a way to locate, let alone 
enter the second one. It's filled for about 0,4GB though, so it's 
already in use.

PS: sorry for the ot but i think i have a chance here to get a
clarifying answer,
I really wanna know this!