Microsoft Virtual PC installation kills entire lan.

One of users installed the Microsoft Virtual PC software on their laptop. Minutes later the entire LAN stopped working with users being disconnected from all servers they were connected to. My first thought was that the hub(s) had died but they looked ok with lights flashing merrily. Trying to ping an ip address on the network was returning the correct ip some of the time and returning a “destination host unreached” from a particular ip address on the network. This wasn’t a hub/router or anything -this is when we found the ip address was the computer that had Microsoft Virtual PC installed on it – at the same time the network died.
We rebooted the pc and it just hangs at the welcome screen with no attempt to log on or provide the ctrl-alt-delete option. Rebooting into safe mode I thought I would uninstall the application. However when you try to uninstall it you get the message “The Windows Installer Service could not be accessed. You may be running in safe mode or Windows Installer may not be correctly installed.” Looking at technet and google gives no clue, apart from running a command after you’ve rebooted normally (not available as it won’t reboot normally!).
I then ran msconfig, selected base mode startup and rebooted. This allowed me to get into the pc. I then started the Windows installer service, ignoring the errors about plug and play services not being installed. I was then able to uninstal the Virtual pc software. Set msconfig back to standard mode and rebooted…..and was unable to log back in 🙁
Incidentally this network outage really confused my Word2003 and it complained about not being able to autosave. After clicking ok to several buttons it then prompted me to send the report to Microsoft. I did and it told me there were updates to Office 2003 – and the one available was to prevent Word becoming unresponsive when trying to autosave! So its definately worth keeping an eye out on the Office update page
Update Fixed the swine software. The machine was refusing to boot unless I went into safe mode and did not select Networking option. This led me to another conclusion that there was something wrong with the networking side still (after having uninstalled the virtual machine software). Sure enough, under device manager, each network card appeared – twice – the standard one and a virtual one. However trying to delete the network drivers produced a message “this device is needed to reboot the machine – go away ha ha ha” or words to that effect. I therefore disabled them (which to me is almost the same as deleting them), rebooted into normal mode and the machine logged on. I then tried to delete the devices again – same problem. At this point I didn’t have an ip address on the network card so I looked at the network card properties – and there was a “microsoft virtual network” component. Uninstalling this gave the message “this will delete from your entire system – are you sure” at which point I started to gain some hope back, and the chance of leaving the office tonight instead of having to rebuild a laptop….. As soon as I hit yes, I got the popup to say I was connected to the network, an ip address and no trace of the swine virtual pc software on the machine.
Now all I have to do is create a group policy to stop users attempting to install this software on any machine anywhere. 🙂