Apologies as I appreciate this has probably been asked and answered a zillion times. I have had my MAC about 6 weeks and love it. I am trying to ween myself off my PC, but at the moment am running it sat next to the MAC. I run a business and use SAGE which isn't available on MAC, so I know that I have to do something Windows based on the MAC. Could someone kindly help explain what I need to buy. I don't want Bootcamp - as I want to use MAC and Windows simultaneously. So I know I need to buy Parallels. It's the next bit I am stumped with. Can I use my OEM disc from my Mesh PC to install Windows Vista on my MAC or do I need to buy a new OEM or FULL version. Thank you so much.