First go to windows explorer-tools-folder options-
view-clear or leave blank-Hide extensions for known file types and then
click OK.
Select your Notepad file and right click on it go to rename
and change extension from txt to doc. and click ok.
On question Do you want to change it click yes.
And that is all if you have Microsoft Office Converter install with your
version on Office,if not
in first opening of that file in word,office will ask you to install
converter,if you are not save your office installation files on hard
disk,insert Office CD in your cd drive and click ok to install converter.
That is all,i hope this will help.