It would seem theoretically possible to install multiple versions of IE on the same machine using Sandboxie (or any other sandbox program). To do this, you would do the following:
- Uninstall the current version of IE from your machine.
- Create multiple virtual hard disks (VHD).
- Configure Sandboxie to store its sandbox files on a specific drive letter like N: for example.
- Mount one of your VHDs to N:. Run the IE 7 install file in the sandbox which should actually install IE 7 in the sandbox itself, leaving your OS unchanged.
- Dismount the IE 7 VHD and mount what will be your IE 8 VHD to N:.
- Run the IE 8 install file in the sandbox to install IE * in the actual sandbox.
- Repeat this process for all versions of IE that you wish to install, but do not install any IE version on your unboxed OS.
- Lastly, let's assume that the version of IE you use for regular browsing is 10 (this is the version that you don't use for testing browser compatibility). It is also installed on its own VHD, but is automatically mounted every time you start your PC. Whenever you want to test browser compatibility, you dismount the IE 10 VHD and mount, say, the IE 7 VHD. When you're done, you switch back to the IE 10 VHD.
The only downside to doing this is that you would always have to run your primary browser in the sandbox which could probably end up being a bit of an annoyance. However, in spite of that, I'd like to know if my idea here would actually work.
FYI - I know that I could embark upon a quest to actually try this on my machine, but, even I did so and it initially appears to work, there could be any number of quirks or caveats that some of you might already be aware of that I wouldn't find out about until way later down the road.