I am able to install Gusty server but when I reboot I get the following error:

Starting up ...
PANIC: CPU too old for this kernel.
I am running a Pentium M 1.86. It's not that old.

I found a solution in this thread.

load feisty install, press alt+f2
mkdir /mnt/hd
mount -t ext3 -o rw /dev/sda1 /mnt/drive
chroot /mnt/drive
apt-get install linux-image-2.6.20-15-generic
apt-get remove linux-image-2.6.20-15-server
I am unable to mount with the server cd. So, I booted with the desktop cd and was able to mount. When I run the first apt-get command it asks to insert the server CD. Virtualbox will not let me change the iso in CD settings since it is booted. I then tried doing the same from the server CD skipping mounting because it won't. I get the same error to insert the server CD and the server CD is mounted. Any ideas on getting Gusty server installed in Virtualbox? I am installing server on Virtualbox just for learning.