The DHCP server has no install function and therefore also does not have an uninstall function either. The DHCP server runs as an application without any install, just run it and stop it as you wish.
If you are using the DHCP server as a service then you have to remove the service. To remove the service, you can either just hit the stop followed by the remove button or you go into the services applet of windows and remove the service there. Please keep in mind that you need administrator privileges to do so.
Some people that have used the HTTP function of the DHCP server software, have experienced that the browser shows the DHCP status page even when the software is not running. This is due to the browser and its cache. Please just clean your browser cache in that case.
After you have removed the service and cleaned the browser cache, the DHCP server software is completely removed from your system.