Consider following situation: There are multiple instances of same type device attached to your computer. For example, there are two devices with Device Instance Path like:

Device 1: PCI\VEN_XXXX&DEV_YYYY&SUBSYS_00000000&REV_ZZ\1&01;
Device 2: PCI\VEN_XXXX&DEV_YYYY&SUBSYS_00000000&REV_ZZ\1&02;

They have same hardware IDs (PCI\VEN_XXXX&DEV_YYYY&SUBSYS_00000000&REV_ZZ). You may encounter following driver installation issue:

1. When there is no inbox driver available for this type device, you may use Device Manager to launch “Update Driver Software…” wizard from the menu “Action ->Update Driver Software” when you select Device 1, and provide the location of vendor’s driver if Windows can’t find the driver automatically. Finally, you installed driver successfully to the Device 1. However, the Device 2 may still has no driver installed after Device 1 had been installed, you have to select Device 2 from Device Manager to launch “Update Driver Software…” again to install driver for Device 2 even these two device share a same device driver;
2. When you are updating the driver for both device 1 and device 2, if you still use Device Manager to launch “Update Driver Software…” wizard when you select Device 1, and provide the location of vendor’s new version driver by selecting “Browse my computer for driver software”, finally you updated driver successfully for Device 1. However, the driver for Device 2 may still use old version driver or Device 2 also has a new version driver but doesn’t work as expected;