Or if you don't want two pc's or dual boot you can always run one OS under with virtualbox or vmware player or any number of other virtualization tools. I suggest using Linux as a host as the performance is much faster. I used to run XP under Linux on my old laptop and when I flipped to full screen no one could tell the difference. I've had up to 4 servers running at one time under a Linux host to do a lab test.
Any time I've had to use MSOffice I would just use the free viewers in a virtual XP session to make sure it looked good.