When I wanted to run Linux Enterprise AS 4 on Microsoft Virtual PC 2004 I got error "An internal virtual machine error (13) has occurred" and virtual pc crashed.
It seems that the reason of this problem is a bug in X Window. When Linux boots in graphic mode this error occurs, and you can not boot up your computer. To solve this problem you should set Linux to boot in text mode rather than graphic mode. To do this follow these steps :
- In GRUB menu select Red Hat Linux with the version of the kernel that you wish to boot and type e for edit. You will be presented with a list of items in the configuration file for the title you just selected.
- Select the line that starts with kernel and type e to edit the line.
- Go to the end of the line and type single as a separate word. Press enter to exit edit mode.
- Back at the GRUB screen, type b to boot into single user mode.
Now edit /etc/inittab configuration file and change default runlevel from 5 (X11) to 3 (Full multi user mode), then reboot your computer. Now Linux boots in text mode and virtual machine won't crash anymore.
For more information see this page : Booting Single-User Mode