Try these steps:
1. Rigth click on the doc file.
2. In the context menu, select "Open With" and Choose Program.
3. Select "Microsoft Office Word" (or browse to locate the program, or see Note).
4. Tick "Always use the selected porgram to open this kind of file."
5. Click OK.
Note: In case when you browse to locate an application, it does not get added to the Open With dialog, then try
OpenWithAdd utility.
Hope the above helps.