I am a novice LaTeX user. I am using the proTeXt version.
I am trying to change the font of a document to Calibri (which I have on my machine). Any tips?
General info: proTeXt is a bundle containing, among other things, the MikTeX distribution.
Afaik, there's no way to use Calibri with pdfLaTeX, but you can easily use it with XeLaTeX:
I recommend not using TeXnicCenter (which comes with proTeXt) for XeLaTeX because TXC doesn't support Unicode. Use e.g. TeXworks instead, which comes with MikTeX, so it should be on your machine as well. For some differences in usage between pdfLaTeX and XeLaTeX take a look at Frequently loaded packages: Differences between pdfLaTeX and XeLaTeX.