IIS7:Cannot start service W3SVC on computer '.'

Issue:

Error while restarting IIS
i.e. after stopping IIS when i start again i hot this error
Cannot start service W3SVC on computer '.'

Resolution:

1. Run -> appwiz.cpl -> Turn windows features on or off -> Check "Windows Process Activation Service"
2. That's all.

and also check this

You should check to see that all of the following services are started, or at the very least, not disabled: HTTP, Windows Process Activation Service, DCOM Process Launcher, and RPC Endpoint Mapper.
You should also verify t hat no other process is listening on port 80. The simplest way to do this is to issue the following in a command window:

netstat -a -o|findstr 80

Thanks