Dear,
Are you sure you installed the update checker?
The update checker is a small software and it will not appear on the main add/remove programs for windows. Just remove it directly from the folder and there isn't anything else for you to uninstall.
When you install Bitcomet, there is an option called software update checking setting and if you select the default option, it will check the software update automaticly.
There is no need touninstall Bitcomet. Just follow the instruction in this post to change the option. :)