xlCompare is a COM-Addin for Microsoft Excel. On your PC you can find it in 3 places:
One of the common issue you may have – ribbon\menu in Excel is not present and when you use desktop tool it starts and exists without showing comparison results. In this case you need to make sure that you’ve installed the right version of xlCompare. It's bitness should match Excel’s bitness. If you have Excel 2010 64-bit, you should install xlCompare 64-bit. In all other cases you should install xlCompare 32-bit even if you have Windows 7.
To check which version of Excel 2010 you have, you need to use Help command on the File tab. This command displays full version information about Excel installed on your PC, including bitness. After version number there should be written 32-bit or 64-bit.