Virtual PC 2007 team introduced a second device that was available on Windows Vista and Windows Server 2008 virtual machines.

This device is only available if during creation of a Virtual Machine you select Windows Vista or Windows Server 2008.

The smoothest way to get sound in a Windows 7 virtual machine is to select the setting as shown in the above picture.

If you have already created a VM without selecting this setting there will be another popup after the VM starts the next time as follows

Device manager would show no sound device either

At this point you will need to reboot the Virtual Machine and install the Audio driver manually. The steps are illustrated in the pictures below

At this point sound should start working in the Windows 7 Virtual Machine.

If you see the text as shown in the above image that says "Hardware-assisted Virtualization is not available on this computer" then most probably the Additions build installed on your Virtual Machine is not 13.820. Upgrading to this build will solve the problem of the bugcheck.

How to uninstall Additions? My VM will just not boot.

• Boot the VM into safe mode
• Uninstall Additions (if that fails delete vmsrvc.sys from %windir%\system32\drivers)
• Reboot
• Install Additions build 13.820 (You will need to install Virtual PC 2007 SP1 and use Additions that is installed in that build). For Virtual Server you need to install the update for W2K8 etc from here.

Note: If Hardware Assisted Virtualization is not available on your machine, the Win 7 VM would run really slow and the CPU consumption would be high too. I would recommend you check in the BIOS if this option is available there.

Technical Explanation:

When Hardware-assisted virtualization is not available, Additions patches the OS kernel to make it perform well inside a Virtual Machine. This patching is OS specific. Since Windows 7 is a new OS the older additions would not be able to patch it. Build version 13.820 has fixes that atleast allow Windows 7 to run (albeit no patches so bad performance), earlier additions cause Windows 7 to blue screen. Recent processors have enhancements that allow OS's in Virtual Machine to run with minimal intervention. This results in better performace even without patches.

I am really looking forward to the first public release of MED-V and then I would have more to say.

1. You have connected the machine running Virtual Server and Administration Website using mstsc but have not used the /console switch, if it is a Vista or Windows 2008 box you have not used /admin switch to connect to the machine.
2. Virtual Server service is not running. To verify this open services.msc and see if the service is running or stopped. If it is stopped and not starting, check if "Virtual Machine Helper" service is running. If Virtual Machine helper service is running you will need to check if "Virtual  Machine Monitor" is running. Virtual Machine Monitor is a kernel component that Virtual Server installs and uses to run Virtual Machines. To check if it is running fine you need to run the following command "sc query vmm". If this returns stopped try "net start vmm". If it does not work, your best bet would be to reinstall Virtual Server.

This is more of a blanket topic where I am listing out the most common scenarios. If you want some specific help you can leave me a scrap.

Here is a quick table that compares both the products.

* Evaluate other criteria's

The important thing the note is that VHD and VMC are compatible across Virtual Server and Virtual PC. So if you try one out and are not satisfied you can always move to the other one.

 The table is a quick reference that I use, it is not intended to be complete. For technical completeness refer the official documentation from microsoft.com.

Virtual Server 2005 R2 SP1: Available at https://www.microsoft.com/windowsserversystem/virtualserver/ 

Do not forget to apply this patch from https://www.microsoft.com/downloads/details.aspx?FamilyId=A79BCF9B-59F7-480B-A4B8-FB56F42E3348&displaylang=en

Virtual PC 2007 SP1: Available at https://www.microsoft.com/downloads/details.aspx?familyid=28C97D22-6EB8-4A09-A7F7-F6C7A1F000B5&displaylang=en 

Virtual Machine Additions if not updated even though you are using the correct build of Virtual Server or Virtual PC still means that you are not running the latest and the greatest. The latest Virtual Machine Additions version is 13.820

On various occasions I have noticed that people on DL's and newsgroups confuse various terminologies related to Microsoft Virtualization solutions.

Here is a quick list of the terminologies I am going to use in my blog

1. Virtual PC: It is the Client Virtualization product from Microsoft. Virtual PC 2007 SP1 being the latest from this stable.
2. VPC: This is probably the most confused term. VPC is another name for the product mentioned above. VPC is Virtual PC and not a Virtual Machine.
3. Virtual Machine (VM): This is what most people mean when they say they are running a VPC image. A Virtual Machine is the container for the Operating System running on Virtual Hardware.
4. Guest Operating System: The operating system running on a Virtual Machine.
5. Host Operating System: The operating system running on Physical Machine.
6. Virtual Server: It is the older offering in the server space from Microsoft. Very stable and reliable product. Now replaced by Hyper-V in 64 bit Windows Server 2008 platforms.
7. Hyper-V: Hypervisor based Virtualization platform from Microsoft. This is receiving rave reviews all around. Someday I will get to blogging about this too.