Doc2pdf (www.doc2pdf.net) is an online website that offers a converter from documents to PDF. You can convert your word documents to PDF for free.
The website says that you can covert powerpoint files to PDF as well. However, when I tried converting my tutorial powerpoints in this sites, some slides came out distorted .
Anyhow, it is best to remember doc2pdf website when you find yourself working with computers with no PDF converter installed.
Here is a step by step guide on how to use doc2pdf to convert your documents to PDF.