Most Windows computers are 32 bit. Shockwave should work on these. The plugin is free and available from Adobe. However, until recently, on 64 bit machines (both XP and Vista) the shockwave plugin did not work without some tinkering. Recently Adobe produced a new version of their plugin (10.3) and in part this does work on 64 bit machines. However there are bugs so some of the models on this site, specifically the lighting model does not work properly at the time of writing. It is also worth noting that Adobe do not produce a Shockwave plugin for Linux. This is a bit of an oversight given that they periodically claim Director Shockwave is 'the' technology to use for elearning interactions.

After you have downloaded the free Shockwave plugin you may still not be able to see some interactions without a box popping up telling you there is a problem and to contact the author. Usually this is because Shockwave is still downloading Shockwave Xtras. These are add-ins to the player that enable 3d or whatever to work. When it has downloaded and installed these Xtras opening and closing the browser usually does the trick and the problem doesn't usually occur again.