Dear Library Computer B,
I understand that, being a library computer, you are likely overused and underserviced. I also understand that the majority of your software is probably outdated and, thus, you run much slower than most of the computers to which I am accustomed. The ideas of antivirus software, high-speed Internet, and any browser other than Internet Explorer are foreign to you. You tool along at insanely slow speeds, completely oblivious to the existence of your more technologically advanced cousins. I am absolutely understanding of this fact, as I know that you are free for me to use at any time.
However, I would like to point out that refusing to display and print PDFs is completely unacceptable. A PDF is not some strange file type; it is quite common and, though I appreciate that you finally decided to print my document, the trouble you gave me was hardly helpful.
Next time, try to be more accommodating, and I’ll try to be more understanding about your horrifically antiquated state.