word pad vs. Word

A little more description would help.  We can only guess based on the limited post.

What model PC?  What Operating System? (this is required on any initial problem post - too many different Dell models).

Do you have MS Word?  and what version?  Do you have MS Word set as the default for all the file types it can handle?

How can I prevent my laptop from periodically converting my Word document into a word pad document ?

No converting is being done. If you don't have Word installed, then Wordpad can open Word documents.