How do you change a file type in window?

Please read me carefully I don't want to convert the file, I want to change the file type. If you select property for a file it will give you a 3 letters file type. That's what I want to change. Renaming will only let you change the rest of your file name. Stupid window XP forced a wrong file type to my video file and now I can not change it. Yahoo needs to buy Microsoft not the other way round. Thanks a lot in advance.How do you change a file type in window?open windows explorer:



tools | folder options | view



UNcheck box that says %26quot;hide extensions for known file types%26quot;



click OK.



now 3-letter ext shows up on all files. change it as you would the rest of the filename.How do you change a file type in window?What is the current file type you need to change.