HI. When I uninstall something, the space before install and after uninstall is different(appear much lesser space,5.15G=>5.14G). How can I restore back the lost space?:confused:

Empty your trash.
If you're using Norton or something similar, empty your protected files.
Clear out your temp files and clean up other problems with ccleaner (http://www.ccleaner.com).

Cool, I will try it...