I get a random shutdown (1 to 2 times a week) using build 1970 with Windows Server 2003. Here's what the server redirects me to on reboot: http://oca.microsoft.com/en/response.aspx?SGD=63f5e530-404e-4386-9f93-9b39abd288f9&SID=10 Is this a driver issue with a parallels driver? this will occasionally kill OS X as well, causing the whole machine to shut down and restart.
