When for a job and got this strange thing where the icons are missing from the network connection folder in windows 7. One of the solution is the Network connection Services is not starting, that why the icons are not appearing on the system. You can start up the services and check to see if the network connection services is started or had been disable by someone (Or Virus?)
And just modified it from what ever startup type to manaul (Default) and start the services. Vola! the icons appear again. This is the same for Windows Printer icons, if it disappear, it is likely the print spool services is not started up. So just start the print spool services and all your printers icons will be back.

But some time print spool services stop with a reason behind and you might need to troubleshoot and solve the puzzle before it can start up again properly.

Best Regards
Hickural