First few steps.

Configuring your environment.

I don't think that, downloading XAMP or WAMP software bundle and installing will be  that much a big deal. So I'm not gonna guide you that much in to it. But these problems might occur when you are setting up XAMP or WAMP for the first time on your PC

After you install WAMP or XAMP,  you might see that,  WAMP Icon might not show itself as online. OR simply the service might appear as started.

Following can be real reasons behind it. I'll explain one by one.

You might have configured IIS server on your computer.
If so,

Go to services, (Dunno how:  press win key+ R--> Then type services.msc)

Stop following service--> World Wide Web Publishing Service

You might have installed and using Skype on your PC.

If so,
Open Skype, Then Select Tools from the menu bar--> Then select advanced settings from the left side bar.
Then select connection from the left expanded menu. Untick use port 80 and port 443 for additional incoming connections.
Restart Skype.

If you have installed MSSQL Server,
Open services --> Then stop SQL server reporting services SERVICE.

This will solve your problem.