Very often registry permissions in Windows get messed up.  Almost all of the time this makes different programs not to work at all. I will cover the situation when there are no items shown in the Device Manager e.g. Device Manager is empty.  If you try to restart the computer, run spyware scan and  even rescan the devices directly from device manager no items will be shown in the device manager. After some testing I’ve found that this is registry permissions related issue. You must use the Registry Editor in …

Some malwares disables the registry editor to prevent removal of their startup entries. Usually the message reads like
Registry editing has been disabled by your administrator
Basically the malware adds the registry entries
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableRegistryTools
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableRegistryTools
and puts a value of 1 for them. This prevents the registry editor(regedit.exe) to be started.
This can be easily solved by changing the value from 0 to 1 or just delete DisableRegistryTools entry. Since the registry editor cannot be started I’ve create a VBS script file to restore the options.