If you want to open a Microsoft Word file do not double-click it in My Computer or right-click and use the Open option. If you do, you may be asked to save it, which is the opposite of what you want.
Either right-click the file and choose Open With and select swriter (see the above image) or open OpenOffice.org Writer and use File – Open to open the file.
For Microsoft Excel files either right-click, choose Open With and select scalc (see the above image) or open OpenOffice.org Calc and use File – Open to open the file.
Note
The above is the case if the file associations for .doc and .xls files have not been changed to point to OO Writer and OO Calc respectively. If they have, just double-click the files and they will open in the appropriate OO application.
How to change the file associations
In My Computer (i.e. Windows Explorer) click Folder Options on the Tools menu. Click the File Types tab and scroll down to DOC (typing D once and then scroll is another way). Click Change and select swriter.
For xls files, scroll to XLS and select scalc.