This is probably because Ubuntu assumes you made a mistake. Whatever the reason you need to update the menu.lst file.

First of all lets make sure that you read all the previous articles so we are all talking about the same thing.

1. Install Ubuntu 9 on Virtual PC 2007.
2. Update the menu.lst after install.
3. Update the menu.lst again after updating the kernel.

From time to time Ubuntu will update various software, (or you can do it your self,  System > Administration > Update Manager. Any one of those update might be a brand new kernel update, in that case you will need to edit the menu all over again.

1. Open the terminal , (‘Applications>Accessories>Terminal’)
2. At the cursor type ‘gksudo gedit /boot/grub/menu.lst‘, (without the quotes), press enter.
3. Enter your password if you have to.
4. Look for the first boot option

   ## ## End Default Options ##
   title ...
   uuid ...
   kernel ...

5. look for the entry that mentions ‘Kernel’.
6. Add ‘noreplace-paravirt‘ at the end of it.
7. Save the file
8. Close the editor.
9. Tell Ubuntu that you changed the file:

   sudo update-grub

10. Reboot and everything should be back to normal … until you update again.

NB: If you cannot boot at all, (because your screen is black or throwing some errors), simply follow the same instructions in the first article on booting up Ubuntu.

NB2: If you still have a question, feel free to go to the forum and I’ll try to help as much as I can.