It sound like you need to download the more common x86 version. Here is the link to the x86 download: Download details: System Update Readiness Tool for Windows Vista (KB947821) [January 2010]
Sorry to have to make you do another download. This install should be pretty easy. First, you run it. Then let it initalise. Once it has done this, you click OK the prompt, and let it run for 15-30 minutes. Then you click Finish.
Image showing initialising. Do nothing here:
Image showing where to click OK:
At the end click Finish. There is nothing more to it.