Install:
Make sure that you have closed TimeLeft before installing, otherwise new TimeLeft version will not be installed.

Uninstall:
You can uninstall TimeLeft using standard Windows tools. Go to Start=>Settings=>Control Panel=>Install and Uninstall Programs, find TimeLeft in the list of applications, select it and press Add/Remove button.
Note: Make sure you have closed TimeLeft before you proceed with uninstall, otherwise some files and registry settings will not be removed.