Since S&T doesn't use hardware acceleration, this problem is unlikely to be caused by the video driver. S&T actually works fine even on SVGA, i.e. with no manufacturer-provided video driver.
I wonder: Do the pushpins show up on the pushpins set? What's the symbol? Some of the symbols are really inconspicuous -- there's one that's just an empty circle, and is indistinguishable from the empty circle used for, say, a city. See screenshot.
Also, it is very helpful to give a step-by-step list of what you did to get to this problem. It should be as detailed as: "I started up
Streets & Trips, then I clicked on this button, then I dragged this to here, then I typed ABC into box XYZ." The industry terminology for such a list is "repro steps" -- i.e. what you need to do to reproduce the problem on another computer. This helps put all the important information up-front, rather than having to go through "20 questions" style information-seeking.