Eugene's observations

Sometimes the presense of the current, possibly corrupted, device driver for a hardware component prevents installation of a new update.  This may account for a device appearing for a second them immediately disappearing.  Uninstallation of some drivers requires the following steps:

1. Run CMD.EXE to get a command prompt with Admin privs
2. Type set devmgr_show_nonpresent_devices=1 then <enter>
3. Start devmgmt.msc 

Within Device Manager Click Show hidden devices on the View menu.  Now you can right click the offending itme and uninstall it.

Note that although this shows ghost entries, not all can be safely uninstalled: those that are temporarily unconnected for example.

 In the unlikely event that this is to be a permenent change, it has to be set in the System properties, Advanced tab, Environment variables.