Clean Install
Reformatting your hard drive (erasing everything on your hard drive, including the programs that are installed) is something that only the brave should do. When you reformat your hard drive, you have the option of starting over from scratch and reinstalling Windows from the roots up (this is referred to as a clean install, and some people do this every so often just as a maintenance routine). This gives you more options. Windows Vista uses the NTFS file system. It is possible to configure your computer as a dual-boot system if you would like to run Windows XP as well. Sometimes users choose to run a dual-boot system so they can A/B the way Cubase functions on both operating systems. Again, I usually stick to the “keep it simple” principle and recommend choosing just one operating system. You’ll probably end up using just the newest operating system down the road. For Macs with Intel processors, this means you can run Windows on your Mac.
Note
If you want to find more info on dual-boot systems, try Googling your operating system (Mac or Windows) along with the words “optimize” and “audio.” Various publications and Cubase user groups are always putting new information on the Web. Whether it strictly pertains to Cubase or another DAW doesn’t matter. They all require something similar from an operating system.