File association with Excel problem

Hi,
in my application i can a export Data as an Excel-XML File, but first i need to check:
-Is Excel installed, and get a path for it
-make File association *XML-File with Excel

My try:
i use a Funktion MsiLocateComponent(...) to check if Excel is there, this works, but there is an problem, if someone has a newer version of Excel after i finish my application??
That means my solution is to static, if i check only for a registry key like "{0638C49D-BB8B-4CD1-B191-052E8F325736}" <<--- this is for Excel 2007,
and this is for Excel 2010 {538F6C89-2AD5-4006-8154-C6670774E980},but if there is an "Office-Excel 2015" with unknown Registrykey after i'm finish my work, they dont find a Excel .... :(
Does anyone have an idea if there is an better way to check if is Excel installed and where is the path to Application?

Next step is to check if is XML file associated with Excel?
Sorry i don't have an idea how to check this ...

Thanks for any help
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