I have just had to attempts at downloading and running SpeedTester, with the most PECULIAR results. When I run the install file, it installs a program called IMPLANT, which is obviously some kind of medical software. Unfortunately no Uninstall facility is provided. I downloaded it twice just in case I had had some kind of complete mental breakdown, but the second download did exactly the same thing!
This happens if you have files in your temporary folder that are waiting to be installed. There are two ways of avoiding this problem; you can clear your temporary folder and then re-attempt to install the Speed Tester, or easier still, you can save the Speed Tester to your desktop and install it from there.