I guess a system builder would know. I installed my OEM like any other Windows OS, I plopped the CD in the tray, closed it and away it went. I would have preferred a retail version and would have purchased one except that XP Pro 64 bit is only available in the OEM version. Now I wish I would have just gone with the retail 32 bit and I would be able to use it on another PC when this one dies. I have Win7 running in a Virtual Box (the one they had for free download that will die in June) and I'm not sure I will ever want to upgrade to it.