Dual-Boot (XP/7) Data Sharing

First I'd like to say hello all, this seemed like a good forum to post my question. Lots of good info and intelligent people here, so I took the time to register so I can figure out if what I'm doing is gonna mess up anything if I attempt it.

My computer is set up to dual boot WinXP and Win7, mostly for gaming compatibility purposes, but I love both OS equally to be honest. I'm trying to make both operating systems basically store and retrieve as much data from the same places as possible without destroying anything. For example, this is what I did so far...

- All drive letters are identical in both OS, to ensure maximum compatibility if running the same program on either OS.

- I have a shared Program Files folder which contains any programs that both OS can run and aren't entirely dependent on the correct registry keys on my "shared" hard drive, separate from my dual partitioned with the operating systems. Also on this drive is where I install my games and just about anything else both OS will use.

- Both OS use most of the same User's folder. I consider 7 my 'main OS', so my XP installation uses Win7's Documents, Music, Downloads, Favorites, and Videos folder, as well as a couple other of the personal settings folder. This works great for my games, both OS share most of my save game files so I can load a game in either OS and there's my progress.

So far everything is working great, but I want to take one final leap and I'm not sure of the effect, mostly because I'm not educated enough about program application data and what kinds of settings they store. Programs seem to store personal data in folders known as "Application Data" in XP and "AppData" in 7. From my understanding, this is pretty much how it goes... (XP Folder then Win7 Equivalent)

x:\Documents and Settings\id\Application Data == x:\Users\id\AppData\Roaming

and

x:\Documents and Settings\id\Local Settings\Application Data == x:\Users\id\AppData\Local

I know how to change where XP stores application data via the registry, what I'm wondering is will there be some kind of negative effect in doing so? Will it mess up my program data? This would be the last thing I can think of doing to minimize the amount of wasteful data stored between my operating systems. From what I'm seeing the programs I happened to install on both have exactly the same AppData in both folders.

I know this post is quite old, but Not only do I have an answer, based on my own, personal experience, I also hate to see questions like this unanswered. :) Plus, it ties into what I was looking for (though it obviously doesn't answer my question - for that, I'll create my own thread).

As my system specs show, I've got a very similar setup, and like you, I've been trying to consolidate as much as I can (though I'm trying to take this consolidation further than that). So far, I've successfully been able to "move" the documents folders in XP to exactly the same architecture that 7 has, with no ill effects. The only thing I've had to do that I REALLY want to find a "fix" for is the permissions. Since there are 2 separate OS's involved, the account ID's from each OS are incompatible with the other's "Administrators" groups. Thus, I've had to give the "shared" documents folders full permissions to Everyone (which I hate, but I'm the only one who uses this box, so the risk isn't as bad as it could be). I'll describe my objective fully in my own thread, but what I want to try to do is "clone" the Windows 7 account into XP, but so far, no luck. Doing this, I'll be able to remove the full permissions for Everyone, which will make me feel better. :)