I just installed Wampserver 2.1 on my windows 7 64bit computer and the icon that should turn green, turns orange, saying that the server is not ready.
The result is
I struggled with this for hours on end on different machines. Often one solution did not work on the next machine. This is what I, by trial and error, found out worked like a charm every time.
Installed WAMP on win7 POS
Finished. No need to edit httpd.conf, no need to edit hosts-file and no need to disable IIS.
A total install of WAMP following these steps take well under ten minutes. Hope it does the trick for you as well.