Not able to upgrade and install any software

[rohkap4444]

I am Rohit and I am new to Ubuntu. I want to upgrade Ubuntu by going to System Settings--System -- Update Manager.
this error is coming:-
'E:Encountered a section with no Package: header, Eroblem with MergeList /var/lib/apt/lists/extras.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages, E:The package lists or status file could not be parsed or opened.

I am very frustrated as I have 5 year old laptop and I am not able to boot from USB bootable pendrive or USB CD Drive to install Ubuntu 12.04. Is there any other way so that I can do the upgrade.

[dino99]

Tell us what you try to ugrade (which actual ubuntu to which one)

Please post the output of (from a terminal):

cat /etc/apt/sources.list

[jerrrys]

Open a terminal and enter:

sudo rm /var/lib/apt/lists/* -vf

sudo apt-get update