Jag satte precis upp en ny virtuell miljö och använder mig då av Virtual PC 2007 och kör en grundmall för OSet och sen differentiella diskar.
Problemet som självklart uppstod när jag skulle lägga med den andra maskinen i min Active Directory domän var en MAC-address konflikt. Jag har tidigare dragit in tredjepartsverktyg alternativt använt drivrutins features för detta. Men jag hittade en underbar guide för att använda registereditorn. Det fungerar på i stort sett alla Windows versioner.

Goto command prompt and type “ipconfig /all”, and

    I. Record the Description for the NIC you want to change.

    II. Record the Physical Address for the NIC you want to change.  Physical Address is the MAC Address

b.     Goto command prompt and type “net config rdr”,

c.     Remember the number between the long number (GUID) inside the { }.  For example, in the above “net config rdr” output, for MAC address “00C095ECB793,” you should remember {1C9324AD-ADB7-4920-B02D-AB281838637A}.  You can copy and paste it to the Notepad, that’s probably the easiest way. 

d.     Go to Start -> Run, type “regedt32” to start registry editor.  Do not use “Regedit.”

f.      Go to “HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlClass{4D36E972-E325-11CE-BFC1-08002BE10318}.  Double click on it to expand the tree.  The subkeys are 4-digit numbers, which represent particular network adapters.  You should see it starts with 0000, then 0001, 0002, 0003 and so on. 

g.  Go through each subkey that starts with 0000.  Click on 0000, check DriverDesc keyword on the right to see if that’s the NIC you want to change the MAC address.  The DriveDesc should match the Description you recorded from step (a.-I.).  If you are not 100% sure about the DriverDesc, then you can verify by checking if the NetCfgInstanceID keyword value matches the GUID from step (c).  
If there is no match, then move on to 0001, 0002, 0003, and so on, until you find the one you want.  Usually 0000 contains the first NIC you installed on the computer.

h.  Once you selected the subkey (i.e. 0000), check if there is a keyword "NetworkAddress" exist in the right side of the window. (See figure 3.)

    I. If "NetworkAddress" keyword does not exist, then create this new keyword:

        i. Click on the drop down menu “Edit -> Add Value”.

        ii.  In the Add Value window, enter the following value then click OK.  (See figure 4.) 
            Value Name: = NetworkAddress
            Data Type: = REG_SZ 

        iii.  String Editor window will pop up at this time (see figure 5.)  

        iv.  Enter the new MAC address you want to modify.  Then click OK.
        (There should not be any "-" in this address.  Your entry should only consist of 12 digits as seen in the figure 5.)

    II. If "NetworkAddress" keyword exists, make sure it shows the keyword type is REG_SZ, and it should show as NetworkAddress:REG_SZ:  .  This keyword might not have a value at this time. 

        i. Double click on the keyword NetworkAddress and the String Editor window will pop up. (See Figure 5.)

        ii.  Enter the new MAC address you want to modify.  Then click OK.
        (There should not be any "-" in this address.

    I.  Goto Start->Setting->Control Panel, and double click on "Network Neighborhood".
           i.  Select the Network Adaptor you just changed the MAC address.

        ii.  Right click on the selected Network Adaptor and click "Disable."  
       Verify the status column for this adaptor changes to "Disabled"

        iii.  Right click on the selected Network Adaptor and click "Enable."
       Verify the status column for this adaptor changes to "Enabled"

        iv.  If for any reason it cannot be disabled or re-enabled, you have to
        reboot your system to make the changes effective.

    II.  Reboot your Windows system. 

k.  Once completing step j (if rebooting the system, wait until the reboot is completed), go to command prompt, type “ipconfig /all” to confirm the new MAC address.

Restore The TRUE Hardware burned-in MAC Address:

a.       Remove the entry you added:

                                                                               I.            If you followed Method 1, then go back to the advanced properties window and remove the entry you add.

                                                                            II.            If you followed Method 2, then remove the "NetworkAddress" keyword you added in the registry.

b.      Use step (j) above to activate the change you make.

c.       Once rebooted, go to command prompt, type “ipconfig /all” to confirm the original MAC address.