First things first, your specs says you have Home Premium, which at the first place doesn't have gpedit.msc anyway so you're good on that part. Regedit - Enable or Disable - Vista Forums
And for Device Manager, quoting TechNet (http://technet.microsoft.com/en-us/l...01(WS.10).aspx
Ability to disable: You cannot disable Device Manager, but you can use Control Panel or Group Policy to prevent hardware wizards from searching for drivers on Windows Update. Alternatively, you can turn off all access to Windows Update
You can also add the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\mmc.exe
Name (String): Debugger
This potentially disables ALL mmc items from functioning. To undo, simply delete the mmc.exe key.