Question about path from Bootcamp to Parrallels

So I am a Bootcamp user. I used it occasionally when someone sent me a Visio document. Now I'm finding that I'm working with a client's access database pretty regularly and switching back and forth is getting to be a pain. So what is the path to make my Bootcamp partition usable to Parallels or am I gonna have to reinstall and all that?

I'll take pointers to a website or a previous discussion if that's handy. Thanks.

 

If it is installed using Parallels Desktop , see Parallels Desktop for Mac user guide from http://www.parallels.com/en/download/file/doc/Parallels_Desktop_for_Mac_User_Guide.pdf chapter 14