So you've been into the services window on your machine and there’s no button to uninstall the service right?
Say you want to uninstall phpdev5. Here's how.
Open command prompt. (Start >> Run >> type 'cmd' and hit enter) this will open up a dos screen.
Type in "sc delete service" where service is the name of the service e.g sc mysql.
Please only do this once you've looked to uninstall a program in add/remove programs and looked for an uninstall option in the programs directory.