I don't know why everybody says you can only install WinXP/SP2 onto Parallels???
I just installed the OEM (WinXP/SP1) disk that came with the PC I bought 5 years ago..... Once it was installed.. I ran Windows Update [61 patches], then I downloaded and installed SP2... no problem..... then I ran Windows Update again [another 35 patches].....
And then I ran Parallels Transporter on my new MacPro.. 10 hours later [yeah its slow].... I had a perfectly working clone of my PC running on my MacPro
Runs flawlessly...