Apache Stopped Working on Windows

Since about 3 weeks ago until today, my Apache server stopped working on Windows XP. I have no idea why it was stopped. I have searched some solutions on Google about this. Some solution asked whether i have Skype installed on my machine, because it was known that Skype can cause conflict with apache because Skype uses port 80 (solution if Skype is the reason is : 1) uninstalling Skype, or 2) modify apache port to 8081 for example).