Can I run Win 7 and XP at the same time?

I would like to do something like the new Parallels for Mac on my Windows 7, or just have the monitor split the screen and run them on two partitions at the same time.

I just built my computer, AMD Phenom X4 and a Radeon 5700.

I was trying to use the Win XP on my cousins Mac in Parallels, but it won't recognize the Mac's GPU. Its a Radeon HD 2600 Pro. I have another forum in the GPU section where I asked about this, but its not the better option because I would have to pay $80 to keep Parallels from expiring after the 17 day trial.