I can give a suggestion and advice.
The advice is that from this point on I think that you make a good back up. Keep it on an external drive. I have been helping out at this fourm for a while and at least 50% of the problems are cause by people who have caused their own problems, primarily because of poor or no backup
The suggestion, is if you think that you want W7, go for it. The public knows this is a great operating system. I had Vista for a year, when they had the preorder for 49.99, I grabbbed it, and now so glad that I did. Mac lovers call the improvements window dressisng. Are enhanced features that make work easier, window dressing? Are features that make computing more enjoyable, window dressing? I don think so. Plus there is a lot more to Win7, than I have time for here.
Cannot really comment on the file, but glad that you are learning. The best way to learn is to teach, I have learned so much in the last couple of months.
Talk soon
Richard