As everyone said it is not possible. Virtual box is the only option between two based Operating system, for them to run simultaneously on the same computer.
Even if it was theoretically possible, you'd need a good spec pc for it... considering how much power a Windows 7 Virtual Machine can use to begin with!
You wouldn't need anything really amazing, quad-core i5 and 8GB of RAM will power a Windows 7 VM just fine. I know because I did it!
For what the OP wants, virtual machines are the only way.
impossible... cuz you would need 2 mice...