Vista will show windows 7 hdd but windows 7 wont show vista hdd?

Please help, i am kind of a computer enthusiast, running vista as my main os on a 750 gb hdd which is what i built the computer with and i wanted to try windows 7, so i threw a 250 gb hdd in, and well my problem is when running vista it will show or recognize the 250 gb windows 7 hdd but when running windows 7 it wont recognize my 750 gb hdd which is well bigger and has all of my music and videos stored on, that i would like to just be able to access from windows 7 not save onto the windows 7 hdd, is this because of how i have them set up as master and slave?