Lastest version of wamp server icon is green but when installed first time your system anyone application working on 80 port wampserver will get error . Wampserver always working on 80 port .
Below things are solutions for change icon color Orange to Green.
1.Check 80 port using applications
Goto the command prompt type netstat . Its will show all 80 port application .We can stop unnessary application and restart wampserver
If you want stop unnessary application Goto the command prompt type services.msc.Search your application.
2. Skype 80 port using application
Goto the Tools -> Options -> Advanced Settings (Left side tab) -> Connection ->Uncheck box ( Use port 80 and 443 for additional incoming connection )