Question : How do you share the root of a Windows 7 drive to an XP machine?

 I just put together a Win7 Pro 64 box and want to share an entire (secondary) drive to my old XP machine.  I have never had issues doing this between XP and/or Vista machines.
  I am able to share an entire XP drive to the Win7 machine but not the other way around. The Win 7 drive shows up in XP, but trying to use it results in an "access denied" message. I *am* able to access shared folders on the Win7 machine from the XP box.
  Does anyone know the secrets to sharing a Win7 drive to an XP machine/user? I have tried a multitude of combinations of users, sharing, and security settings! TIA

Answer : How do you share the root of a Windows 7 drive to an XP machine?

See if this helps you out - I had a similar problem and found this to be a nice clear guide.

http://www.howtogeek.com/howto/windows-7/share-files-and-printers-between-windows-7-and-xp/

Good luck!