If you are using Wamp2.0, and the icon only turns yellow in your tray, and you try to make your server online / offline, and say that some service has not started, then a ix is.
Try reinstalling. Always do this before anything else.
Close all the programs you are not using.
Note that Skype will cause an error with Apache.
If it does not completely uninstall with the registry keys. Use regedit in your computer * Note that it will require administrator privileges *