What you will do is go in Device manager right click the bang, then go to properties, then to the details tab in that tab there should be a drop down that is already populated with the device instance ID. In the dialogue below the drop down there should be a string of gibberish. It looks something like this PCI\VEN_8086&DEV_293E&SUBSYS_0211128&REV_02\3&172E68D D&O&D8.
Then go to this site pcidatabase.com
Put in the 4 digit number that comes after VEN_ as the vender id. Then put in the 4 digit number after DEV_ as the device ID. Click search. If you get multiple results find the exact match to the information you searched for. This will give you the device the driver is missing for and help narrow your search.