How can I install ubuntu 11.04 on my laptop DELL Latitude E6420?
I see this at the ubuntu sites
The system is available in some regions with a special image of Ubuntu pre-installed by the manufacturer. It takes advantage of the hardware features for this system and may include additional software. You should check when buying the system whether this is an option.
Standard images of Ubuntu may not work at all on the system or may not work well, though Canonical and computer manufacturers will try to certify the system with future standard releases of Ubuntu.