It might be helpful to know:

1. What OS was on the old old machine.
2. What OS is on the new old machine.
3. What version of Word you were using on the old old machine.
4. What version of Word is on the new old machine.
5. Was either Word version part of an "Office" suite of programs, or were they both the "dummy" versions that came with most preloaded machines.

There have been at least three, possibly four, recent "Word formats." There have generally been import/export filters available to import any Word format into any Word version, but in many cases you can't export (save as) in all the formats that you can open.

It's possible that you're just missing one of the filters that you need, although it's hard to see how that would produce the symptoms as you've described them.

It's possible that Geek squad has somehow "lost the registration" of the Word version on the new old machine, especially if the machine came with a "Works" version and a previous owner upgraded to a "real Word." An unregistered Word may "loose functionality" and be unable to save format details.

It's also possible that you've just got something strange set in Word "options," but there have been several changes in where those options are and how you get to them in the recent versions. (In some versions you can set a default folder to save in that's pretty "persistent," so if you opened a Wordpad item by clicking it open and did "Save As - Word" without changing the destination folder the .doc/.docx file will be in a different place than the .txt/.rtf file, so it might look like it got changed back? when actually it just wandered off to somewhere you haven't looked.)

John