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Select all the files you want to rename, press F2, or right-click on one of the files and select Rename. All of your file selections will disappear except for one, but don't panic: Type in your new name and click Enter. That's it! One file will be now be named "renametext" and the others will have sequential numbers in the format of "renametext (1)" and "renametext (2)" and so on.
Not exactly what you are looking for but might work for you.
Assuming Russell is actually using DOS (we still have machinery running DOS exclusively on 386 and 486 machines), I think Henry's idea is probably the best place to start. The DOS ? and * wildcard characters don't always give exactly the expected results.