Wordpad would just stick ".wri" on the end, and Word will stick ".doc" on the end.
The solution is to turn off Microsoft™ BabyTalk™ (with added SecurityRisk™).
Open Windows Explorer (not Internet Explorer, the other one). Choose Tools -> Folder Options, and click the "View" tab. Clear the checkbox next to "Hide extensions for known file types". Click "Apply to all folders" (never seems to make any difference but it helps to insist) and then click OK.