/boot/grub/menu.lst was a very old way of configuring GRUB and it's boot options. I think I used to use it like that in Ubuntu 10.10 and below. Right now, if you are using a updated version of Kubuntu, the option should be in
Just do something like:
sudo nano /etc/default/grub (To edit via terminal)
sudo gedit /etc/default/grub (To edit via GUI)
The option you want to edit is:
You can either add what you want after the splash parameterin the first line or add inside the quoted part in the second part.
After that, save the file and type in the terminal
update-grub so the grub gets updated and adds what changes you have done to the boot part. Then just reboot the PC and enjoy the change.