It is a very small section of the hard drive to run the PC. And yes, it is susceptible to viruses, which is why I will only use it for my school assignments. Windows is a virus magnet and this is no different.
Which may be something to consider Miaheat.
Yahoo may be a better choice for you and your friend, but if you wanna find out more about what I have, I got it from the apple store sight, but the direct link is vmware dot com. But remember, it's cheap because you hafta have your own operating system disk.
I think virtual PC is all inclusive. But it's pricy