Win7 VPC and XP Mode crash upon restart

Question

I have Windows 7 Virtual PC (64-bit) with Windows XP Mode in my Win7 Pro x64 host setup.  When I first installed both programs, I had no trouble shutting down or restarting XPM...
...But just recently, after a restart, my VPC crashed.  The sequence is as follows:  After shutting down XPM, the window disappears, to be replaced by the typical scrolling green line with the message "Shutting down the virtual machine..." 
The message changes to "Starting the virtual machine..." as it attempts to restart XPM; and just as it is about to open the XPM window, the error pops up,
"Windows Virtual PC has stopped working".
At that point, I am obviously forced to shut down the process.  The only way I can start XPM is from a cold start.  I cannot perform a restart of any kind, whether it is a cold restart or a restart following the installation of a program that requires
a restart.  I have to shut it down cold before I can start it again.
My first suspicion is that I installed a program that caused one of my Win7 components (whatever is required for VPC and/or XPM to function properly) to malfunction or disappear from my setup.  But I have yet to notice any other program exhibit abnormal
functionality or crash completely.  Nor have I tinkered with the registry.
I tried removing VPC and reinstalling, but it still crashes when I attempt to restart XPM.  I have not yet tried removing and reinstalling XPM as of yet, but I suspect that might not work, either.

Answer 1

Has anyone tried the 32-bit VPC in a 64-bit Win7 environment?  Or will it not install?  And why does VMWindow.exe load into the system32 folder...
C:\Windows\System32\VMWindow.exe
...When the VPC version installed is the 64-bit version?
Here is error code from a more recent attempt to restart XP Mode:
Log Name:      Application
Source:        Application Error
Date:          12/4/2013 3:01:24 AM
Event ID:      1000
Task Category: (100)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      BlueXmas64
Description:
Faulting application name: VMWindow.exe, version: 6.1.7601.17514, time stamp: 0x4ce7b2e6
Faulting module name: ntdll.dll, version: 6.1.7601.18247, time stamp: 0x521eaf24
Exception code: 0xc0000374
Fault offset: 0x00000000000c4102
Faulting process id: 0x1804
Faulting application start time: 0x01cef0be73fb796d
Faulting application path: C:\Windows\System32\VMWindow.exe
Faulting module path: C:\Windows\SYSTEM32\ntdll.dll
Report Id: 447afaab-5cba-11e3-8cf2-bc5ff45ce61c
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Application Error" />
    <EventID Qualifiers="0">1000</EventID>
    <Level>2</Level>
    <Task>100</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2013-12-04T08:01:24.000000000Z" />
    <EventRecordID>19272</EventRecordID>
    <Channel>Application</Channel>
    <Computer>BlueXmas64</Computer>
    <Security />
  </System>
  <EventData>
    <Data>VMWindow.exe</Data>
    <Data>6.1.7601.17514</Data>
    <Data>4ce7b2e6</Data>
    <Data>ntdll.dll</Data>
    <Data>6.1.7601.18247</Data>
    <Data>521eaf24</Data>
    <Data>c0000374</Data>
    <Data>00000000000c4102</Data>
    <Data>1804</Data>
    <Data>01cef0be73fb796d</Data>
    <Data>C:\Windows\System32\VMWindow.exe</Data>
    <Data>C:\Windows\SYSTEM32\ntdll.dll</Data>
    <Data>447afaab-5cba-11e3-8cf2-bc5ff45ce61c</Data>
  </EventData>
</Event>