LAST EDITED ON 07-21-08 AT 05:32 PM (EST).doc is the standard extension for Microsoft word, let me check something that might work.
Usually when I have Word it takes over an insists all the files are it.
this link might help.
What operating system are you using.
The other option is to right click the file and use open with and Word should come up as one of the options.
ETA: I think the solution is to change which program your computer thinks a .doc file belongs to, not change the ending that the program saves them as.