There are some ways to start & stop IIS, I am listing few ways.

IIS 6.0

To Stop:

net stop w3svc  
net stop iisadmin  

To Start

net start iisadmin  
net start w3svc

IIS 7.0

To Stop

net stop WAS  press ENTER; type Y and then press ENTER to also stop W3SVC

To Start

net start W3SVC and press ENTER to start both WAS and W3SVC

Another method:-

iisreset /stop

iisreset /start

Just a basic thing but sometimes help…