Error: "Registry Editing has been disabled by your administrator". How to enable?

Some viruses and trojans disable registry editing, so when trying to edit registry in Windows XP you get the following message "Registry Editing has been disabled by your administrator".

How do you enable Registry Editing again if it has been disabled by your administrator?

• How to enable registry editing with gpedit.msc (Windows XP Pro only)
  
  Click Start -> Run -> Type gpedit.msc and click OK -> User Configuration -> Administrative Templates -> System -> Prevent access to registry editing tools -> Right Click Properties -> Set it to "Not Configured".
• How to enable registry editing with reg.exe
  Click Start -> Run. Copy the the following command
  

  REG delete HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableRegistryTools /f

  and paste it in the Run box. Click the OK button.
  
  Then a prompt will come up with this question: Delete the registry value DisableRegistryTools (Y/N)? Type y and hit Enter.
• How to enable registry editing with reg.exe
  
  Click Start -> Run. Copy the the following command
  

  REG add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableRegistryTools /t REG_DWORD /d 0

  and paste it in the Run box. Click the OK button.
  
  Then a prompt will come up with this question: Value DisableRegistryTools exists, overwrite (Y/N)? Type y and hit Enter.
  
  Copy the following command
  

  REG add HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableRegistryTools /t REG_DWORD /d 0

  and paste it in the Run box. Hit enter.
  
  Then it will also come up with the question: Value DisableRegistryTools exists, overwrite (Y/N)? Type y and hit Enter.
• How to enable registry editing with regedit.exe before your systems had checked for ploicies
  1. Disable as much as you can from your startup. Remove programs from your startup folder and such, so as not to lag down the bootup process.
  2. Create a new shortcut on your desktop, point it to "C:\Windows\regedit.exe"
  3. Log off, then log back on.
  4. As soon as you see your desktop, double click on the shortcut. The system does not check for policies until a few seconds after it booted up. If you click on the icon fast enough, it should let you get in.
  After you close it though, it will not open unless you redo step 3 and 4.
• How to enable registry editing with VBS Script
  
  Open Notepad and copy the following VBS script into it:
  

  Option Explicit
  'Declare variables
  Dim WSHShell, rr, rr2, MyBox, val, val2, ttl, toggle
  Dim jobfunc, itemtype
  On Error Resume Next
  Set WSHShell = WScript.CreateObject("WScript.Shell")
  val = "HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableRegistryTools"
  val2 = "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\DisableRegistryTools"
  itemtype = "REG_DWORD"
  jobfunc = "Registry Editing Tools are now "
  ttl = "Result"
  'reads the registry key value.
  rr = WSHShell.RegRead (val)
  rr2 = WSHShell.RegRead (val2)
  toggle=1
  If (rr=1 or rr2=1) Then toggle=0
  If toggle = 1 Then
  WSHShell.RegWrite val, 1, itemtype
  WSHShell.RegWrite val2, 1, itemtype
  Mybox = MsgBox(jobfunc & "disabled.", 4096, ttl)
  Else
  WSHShell.RegDelete val
  WSHShell.RegDelete val2
  Mybox = MsgBox(jobfunc & "enabled.", 4096, ttl)
  End If

  Select everything and copy into Notepad. Save as regtool.vbs onto your desktop.
  
  Open regtool.vbs. And there you go!
• How to enable registry editing with a 3rd party registry editing tool
  Use a third party registry editing tool.
  Create the following key
  

  [HKEY_CURRENT_USER\SOFTWARE\Microsoft\ Windows\CurrentVerson\Policies\System]  
  "DisableRegistryTools"=dword:00000000