Re: 2 hard drives windows vista and 7 question?
If you want to dual boot, that is to say, have Vista on one drive and 7 on the other, and then the ability to switch between the two operating systems, yes. You can do that.
If you want to dual boot, but have both operating systems running at the same time, no, you can't do that.
If you want to have data on one drive that was running Vista, and 7 on the other, and want to access the data on the Vista drive, yes, you can do that with caveats (restrictions).
The restrictions in the last case would be if a game requires an installation that needs to put registry entries into the registry, you would have to also install the game under the OS You want to run it on. For example:
Install game XYZ on the Vista drive. Switch over to Windows 7 (by restarting the system and selecting 7 instead of Vista) try to run the same game - can't do it. You'd have to install the game under 7 as well.
Hope that's clear.