I recently did a migration of a 2003 SBS server to a new Windows Server 2012 host and I think it's worth writing a step by step "how-to" on the process. I am doing this from my notes and memory so this may not be exact but it will give you a good idea of the best practices for this solution. Hope you enjoy it

Prerequisites
SQL Server Standard 2012 (The Trial mode will work)
   Link- http://www.microsoft.com/en-us/sqlserver/get-sql-server/try-it.aspx#tab2
System Center 2012 Virtual Machine Manager (Trial mode works as well)
   Link- http://technet.microsoft.com/en-us/evalcenter/dn205295
Assessment and Deployment toolkit aka: ADK (Don't forget this one, you could end up waiting a long time during migration for this one to finish downloading!)
   Link- http://search.microsoft.com/en-us/DownloadResults.aspx?q=assessment%20and%20deployment%20kit

Phase One

1. Join the newly configured server to the existing domain
2. Install SQL and use domain credentials for install
3. Install SCVMM but use a NEW USERNAME when it prompts for a username. E.G. create a user in the admin group called SCVMMAdmin and input it into the fields when prompted. My understanding of why this is, is because SQL needs to use the domain administrator credentials exclusively for running it's dependent services but correct me if I'm wrong in the comments below.

Phase Two: The P2V Phase

1. Open SCVMM
   
2. Click Fabric> Add Resources> Hyper-V hosts and clusters
   
3. Follow the prompts and point to the wizard to the localhost
   
4. Click VM's and Services>Create Virtual Machine>Convert Physical Machine
   
5. Specify the DC or server that you are targeting for the migration
   
6. Follow the prompts and select "do not start VM after migration"
7. Once the Migration starts I believe it's at this time that it will ask for the path to the ADK

Phase Three: Post P2V Tasks

1. Shutdown the old physical server and start the newly migrated VM
2. Remove local hardware specific software such as APC PowerChute, MegaRAID, etc.

ALL DONE!

...make sure that “exchange form based authentication” is started in the services console.

If it keeps crashing you've got a different problem on your hands that requires further investigation, but in my case a reboot would have fixed it but unfortunately this was not an option for the client and thus I had to manually start it. After doing so, the problem did not re-occur.

I discovered this after I had already dis-joined the computer and was waiting for the computer to reboot. Next time this happens to any of you techs out there, try the steps below and let me know if it works in the comments below.

Source:http://www.implbits.com/about/blog/tabid/78/post/don-t-rejoin-to-fix-the-trust-relationship-between-this-workstation-and-the-primary-domain-failed/default.aspx

  

Just change your computer password using netdom.exe!

netdom.exe resetpwd /s:<server> /ud:<user> /pd:*

<server> = a domain controller in the joined domain

< user> = DOMAIN\User format with rights to change the computer password

Here are the full steps:

1.  You need to be able to get onto the machine. I normally just log in with the local Administrator account by typing, ".\Administrator" in the logon window. I hope you remember the password. If you’re creative and resourceful you can hack your way in without the password. Another option is to unplug the machine from the network and log in with domain user. You will be able to do disconnected authentication, but in the case of a reset machine, remember that you may have to use an old password. Your domain user’s cached credential has the same problem as the machine’s private secret.

2.  You need to make sure you have netdom.exe. Where you get netdom.exe depends on what version of Windows you’re running. Windows Server 2008 and Windows Server 2008 R2 ship with netdom.exe you just have to enable the Active Directory Domain Services role. On Windows Vista and Windows 7 you can get it from the Remote Server Administration Tools (RSAT). Google can help you get them. For other platforms see this link: http://technet.microsoft.com/en-us/library/ee649281(WS.10).aspx"

3.  Extra steps if the machine is a domain controller. If the broken machine is a domain controller it is a little bit more complicated, but still possible to fix the problem. I haven’t done this for a while, but I think this works:

a.     Turn off the Kerberos Key Distribution Center service. You can do this in the Services MMC snap-in. Set the startup type to Manual. Reboot.

b.     Remove the Kerberos ticket cache. A reboot will do this for you, or you can remove them using KerbTray.exe. You can get that tool here: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=17657

c.     Post change steps. Do these in conjunction with 5 below. Turn the Kerberos Key Distribution Center Service back on before rebooting. You should reboot the domain controller and then force replication in the Active Directory Sites and Services MMC snap-in.

4.  Run netdom.exe to change the password.

  Open an administrative command prompt. On Windows platforms with UAC enabled, you will need to right-click on cmd.exe and select "run as Administrator".

a.     Type the following command: netdom.exe resetpwd /s:<server> /ud:<user> /pd:*

5.  Reboot the machine.

Here is more information on netdom.exe: http://support.microsoft.com/kb/325850

Before you get your hopes up, THIS DOES NOT WORK... but if you want to try it, you can via the commands below

Elevated CMD

Run:

dism /online /enable-feature /featurename:Microsoft-Hyper-V /all

Once you go to create a new VM, it will say that virtualization is not enabled at the bios level (or something to that effect) even if it is. Bummer but still pretty cool that you can even get it installed.