This is a great little how-to on hiding and unhiding cells in Microsoft Excel: http://spreadsheets.about.com/od/excelformatting/qt/070814unhidecol.htm
Tag: Microsoft
Show Hidden Devices in Windows Device Manager
If you ever need to display hidden devices in your devide manager, run the following from a Command Line window, or create a short script (show_hidden_devices.cmd) with the following content:
set devmgr_show_nonpresent_devices=1
start devmgmt.msc