The Problem – upgraded Ubuntu kernel and the GRUB menu no longer had a line for starting Windows.

Solution tried: Opened menu.lst for editing using command:

sudo /boot/grub/menu.lst

and added the following section (+ reset default – NB zero-based so item 1 is 0 etc)

title Windows 95/98/NT/2000
root (hd0,0)
makeactive
chainloader +1

Nope – hd0,0 not correct on the dual boot kids computer.

OK ran the following command to see what partitions there were:

sudo fdisk -l

(NB that is an L not an i)

This returned something roughly like:

/dev/sda2
/dev/sda3
/dev/sda4
/dev/sda5

where the sda4 was the Windows partition. So I changed (hd0,0) to (hd0,3) and dual booting worked again.

And to prevent Ubuntu from wiping the Windows entry again I only put Windows under the Debian automagical line.