Not All Systems come with AMT aka VPRO.  If the AMT was ever disabled then it can NEVER be re enabled again.

There is a white sticker on the inside cover that indicates what the AMT mode is or isnt. On the Manageability Mode Options for Dell Optiplex where they say that Management Options of the computer depend on the sticker inside the machine chassis. And if the sticker says 1, AMT is installed on the motherboard, and if it's any other (2, 3 or 4) number, AMT is not and only a motherboard change can change it.

Manageability Mode Options on Replacement System Boards for the OptiPlex™


The OptiPlex™ has one system board per chassis available for dispatch. The system board is shipped in manufacturing mode and the end user or service provider must select the manageability option upon first boot. There are four manageability options that might be seen on the customer order according to the original configuration purchased.
For information on what manageability options were configured when the system was originally shipped, refer to Table 1: 

* The No TLS option only applies to the following countries: China, France, Hong Kong, Israel, Korea, Poland, and Russia.
Table 1: Manageability Mode Labels
When issuing a dispatch, leave a note in the Comments to Service Provider field with the Manageability Mode option that must be selected after the system board is replaced.

The Manageability Mode Sticker on the Chassis Cover for the OptiPlex™


On the inside of the removable side cover there is a 2" x 1" label denoting the manageability mode with which the system was purchased (Figures 1 ).

Figure 1: The Manageability Mode Sticker Location on the OptiPlex

Configure the Manageability Mode on a Replacement System Board

	Note:
	When the number for the manageability mode is entered and confirmed, it is unable to be changed. If the incorrect manageability mode is selected, it is possible the system board must be replaced depending on the option selected.

1. Turn the system off and remove the power cord.
2. Open the chassis cover and locate the manageability mode sticker.
3. Verify the number on the manageability mode sticker.
4. Close the chassis cover, plug the power cord back into the system, and turn the system on.
5. At the Type the number corresponding with your selection: prompt, press the key for the number obtained from the sticker (Figure 1).
   
   Figure 1: Prompt Received After Replacing the System Board
6. At the Continue with selection? (Y/N) prompt, press .
7. After the system shuts down, turn the system back on to continue with normal operation.

Change Manageability Modes 1 and 2 if Incorrectly Selected


It is not possible to change the Manageability Mode when options 3 or 4 have been selected. 
If Manageability Mode options 1 or 2 are incorrectly selected after replacing the system board, correct this by performing the following steps:

1. Restart the computer.
2. Press and hold  while tapping

   at the Dell logo screen to enter the Intel Management Engine BIOS Extension (MEBx) screens.

3. When prompted, enter the password and press .
4. Select Intel (R) ME Configuration and press .
5. At the [ Caution ] screen, press .
6. At the Intel (R) ME Configuration screen, press to select Intel (R) ME Features Control amd Press the key.
7. Press  to select Manageability Feature Selection.
8. Use or to select either Intel (R) AMT or ASF, which are respectively options 1 and 2 when selecting the Manageability Mode on a replacement system board.