After googling for a while, I found it is just as simple as just delete the application! There is another place I could check: /Library/Application Suppport to see if there any OpenOffice folder there. I tried to delete the application. It is gone. So simple to clean an application on Mac, not liking Windows where you might left some registry settings or dll files in <Windows> or <Windows/Systems> or some where in "Program Files" folder. Of course, I have to remove some aliases I places in other use accounts.
Then I installed NeoOffice.app. Its UI is much better than OpenOffice, and it's a complete package with document editing, spreed sheet, presentations, and database. I used the first two in most cases.
The next problem is that my default Open option for documentation or excel files are back to Apple's TextEdit.app and Numbers.app. To change the default Open With is quite simple:
- Select a file in Finder,
- Press Command+I key to open File Information window
- Change to an option in Open with option list.
- Click on button Change All... will change the default for all files like this.
Command+I is a generic Apple Key for information. For file information, you can also change file icon there. Just select the icon of a file, use either menu Edit|Copy or Command+C to make a copy to get the source icon. Then open another file's information window, select its icon then past the source icon (Eidt|Paste or Command+V). To undo it, just press Command+Z.
After several month practice, I am getting used to Mac interface and really like my iMac. It is very stable, fast, easy to use and many more!