So just uninstall the trial version. That's what I just did with my new Dell PC after I installed my personal copy of Office... I used the free version of Revo Uninstaller to get rid of it.
This certainly is not an XPS specific question, but since the general board is read only ... My system, like most I suppose, came with some trial version of Office installed.  However, I had my own version of Office 2010 and installed that.  When I click on the Word icon I created on my desktop, I get Word in Office 2010 just fine and can process documents all I want.  If I click on a .doc file, however it opens in the unlicensed version of Word which presumably came with the machine (I can't find where it tells me what version that is).  The icon tells me that my copy is installed in "C:\Program Files\Microsoft Office\Office14\WINWORD.EXE" .  There is also an Office15 in the Microsoft Office directory, which I would guess is the trial version.  If I go to Apps & Features and the screen for designating default apps by file type, the only choices it gives me is Word and Microsoft Store where the Word is the trial version.  If I right click on a .doc file and select Open With, there is an option to look in the file system, but if I do that and point to the Winword file above, it still opens in the trial version.  95% of my work is on the same handful of files or on new files, so most of the time I have no problem, but it is really annoying not to be able to click on a file.  Suggestions?
Getting Windows to point to the correct copy of Word