I use PowerPoint for work, and I sometimes receive password-protected files that my iMac (OS X, 10.5.8, PowerPoint for mac: 2008) cannot open. If I want to open and work on such files, do I have any options besides running Windows? If I run Windows, should I use XP or Vista? I do not have any use for Windows except getting to those password-protected PowerPoint files. Thanks in advance for your advice.