I have a fully paid for version of Office Home and Student 2010 which I am perfectly happy with.

This morning when I double clicked an Excel file to open it launched a trial copy of Office 365. I have not asked for this trial to be installed and I presume it was included in a recent round of MS updates. I have update set to include Office but I assumed it only applied to installed versions and not to install a new version that's is not free.

I can still get to my 2010 versions of Office but I can't seem to be able to reset the associations back to this version. Whatever I try it wants to open in Office 365 when I double click a file.

Any ideas?

Thanks.