Now, when the trial is up, can JUST the word processor be removed and the files saved, or should they be moved to a CD or a separate folder?
You would need to install the Word Processor on the System Partition (C:\) and the Files on another (D:\). When the Trail Period is up, you would have to revert the System Partition back to the Time before you installed the Word Processor (COMODO DiskShield can do that). But be aware, EVERYTHING on your System Partition (C:\) will be reverted back too; like the Windows System Restore feature.
But now your thinking,
"What if I used a USB Drive, or created a Third Partition (E:\), protected it with COMODO DiskShield, and installed the Word Processor on that. Then just revert the E:\ Partition back when the Trail Period is up? Would that work?".
The answer is: Most probably not.
Because, although you are reverting the Contents of the E:\ Partition back, the Registry entries will still remain in the System Registry: Which is always stored on your System Partition (C:\).
My advise would be, what ever Program you have fell in love with, I am almost certain that there is an awesome Free alternative out there.
As my Mum used to say, "There's plenty more fish in the sea".