Dear Customer,
Thanks for you interest in Microsoft Fixit Center(Beta).
After installing Microsoft Ficit Center on Windows XP, It will take about 15 seconds to copy the troubleshooter from downloaded location to the stored location, during this period, Microsoft Fixit Center can't detect the troubleshooter on the stored
location, so it appears an "Install" button for each item rather than "Run". In that case, you don't need to reinstall the troubleshooter, please restart Microsoft Fixit Center(close and reopen), all button will appear "Run".
If you still have any doubt of this issue, please let me know.