Hello Karl,
Three things to try:
Go to Start => Run and type in "msconfig" {without the quotes}
Click the Services tab.
Make sure that the 'Hide All Microsoft Services' box is not checked.
Make sure that the box for the service 'Plug and Play' is checked.
Restart the computer
If Plug and Play isn't listed:
Go to Start => Run and type in "services.msc" {without the quotes}
Scroll down and double-click Plug and Play. If you receive a
Configuration Manager message, click OK.
In the Startup Type list, click Automatic, and then click OK.
Close Services.
Restart the computer.
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If the Device manager is showing the System Name but not showing any
devices, then check the security permissions on the Registry key
HKEY_LOCAL_MACHINE\SYSTEM\CURRENTCONTROLSET\ENUM .
The SYSTEM account must have full control permissions on this key in
order for the Device Manager to list all the devices in the window.
To access the Registry, go to Start => Run and type in "regedit"
{without the quotes}
To check Permissions, right-click on the key
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Another known cause is the Windows update KB905749 which is supposed to
fix a vulnerability in Plug and Play.
To uninstall an update:
With Explorer set to 'Show Hidden Files and Folders', go to your
Windows folder. Look at the blue text folders and locate the one for
the update. Open this folder and open the folder spuninst. There is an
uninstall executable in there.
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