my ubuntu software center is empty i cannot install any new software

Maybe you need to refresh the package cache. In Synaptic, click “Refresh”, or in a terminal, run:

 sudo apt-get update

after running the command

   sudo apt-get update

im getting this message

Ign http://archive.ubuntu.com natty InRelease
Ign http://security.ubuntu.com natty-security InRelease
Ign http://ppa.launchpad.net natty InRelease
Ign http://in.archive.ubuntu.com natty InRelease
Ign http://in.archive.ubuntu.com natty-updates InRelease
Hit http://ppa.launchpad.net natty Release.gpg
Hit http://archive.ubuntu.com natty Release.gpg
Hit http://security.ubuntu.com natty-security Release.gpg
Hit http://ppa.launchpad.net natty Release
Hit http://in.archive.ubuntu.com natty Release.gpg
Hit http://archive.ubuntu.com natty Release
Hit http://security.ubuntu.com natty-security Release
Hit http://ppa.launchpad.net natty/main Sources
Get:1 http://in.archive.ubuntu.com natty-updates Release.gpg [198 B]
Hit http://archive.ubuntu.com natty/restricted Sources
Hit http://security.ubuntu.com natty-security/restricted Sources
Hit http://ppa.launchpad.net natty/main i386 Packages
Ign http://ppa.launchpad.net natty/main TranslationIndex
Hit http://in.archive.ubuntu.com natty Release
Hit http://archive.ubuntu.com natty/main Sources
Hit http://archive.ubuntu.com natty/multiverse Sources
Hit http://archive.ubuntu.com natty/universe Sources
Hit http://security.ubuntu.com natty-security/main Sources
Hit http://security.ubuntu.com natty-security/multiverse Sources
Hit http://security.ubuntu.com natty-security/universe Sources
Hit http://security.ubuntu.com natty-security/main i386 Packages
Hit http://security.ubuntu.com natty-security/restricted i386 Packages
Get:2 http://in.archive.ubuntu.com natty-updates Release [27.2 kB]
Hit http://security.ubuntu.com natty-security/universe i386 Packages
Hit http://security.ubuntu.com natty-security/multiverse i386 Packages
Ign http://security.ubuntu.com natty-security/main TranslationIndex
Ign http://security.ubuntu.com natty-security/multiverse TranslationIndex
Ign http://security.ubuntu.com natty-security/restricted TranslationIndex
Ign http://security.ubuntu.com natty-security/universe TranslationIndex
Hit http://in.archive.ubuntu.com natty/restricted Sources
Hit http://in.archive.ubuntu.com natty/main Sources
Hit http://in.archive.ubuntu.com natty/multiverse Sources
Hit http://in.archive.ubuntu.com natty/universe Sources
Hit http://in.archive.ubuntu.com natty/main i386 Packages
Hit http://in.archive.ubuntu.com natty/restricted i386 Packages
Hit http://in.archive.ubuntu.com natty/universe i386 Packages
Hit http://in.archive.ubuntu.com natty/multiverse i386 Packages
Ign http://in.archive.ubuntu.com natty/main TranslationIndex
Ign http://in.archive.ubuntu.com natty/multiverse TranslationIndex
Ign http://in.archive.ubuntu.com natty/restricted TranslationIndex
Ign http://in.archive.ubuntu.com natty/universe TranslationIndex
Get:3 http://in.archive.ubuntu.com natty-updates/restricted Sources [14 B]
Get:4 http://in.archive.ubuntu.com natty-updates/main Sources [98.2 kB]
Ign http://ppa.launchpad.net natty/main Translation-en_IN
Get:5 http://in.archive.ubuntu.com natty-updates/multiverse Sources [1,893 B]
Get:6 http://in.archive.ubuntu.com natty-updates/universe Sources [22.1 kB]
Ign http://ppa.launchpad.net natty/main Translation-en
Get:7 http://in.archive.ubuntu.com natty-updates/main i386 Packages [286 kB]
Ign http://security.ubuntu.com natty-security/main Translation-en_IN
Ign http://security.ubuntu.com natty-security/main Translation-en
Ign http://security.ubuntu.com natty-security/multiverse Translation-en_IN
Ign http://security.ubuntu.com natty-security/multiverse Translation-en
Ign http://security.ubuntu.com natty-security/restricted Translation-en_IN
Ign http://security.ubuntu.com natty-security/restricted Translation-en
Ign http://security.ubuntu.com natty-security/universe Translation-en_IN
Get:8 http://in.archive.ubuntu.com natty-updates/restricted i386 Packages [14 B]
Get:9 http://in.archive.ubuntu.com natty-updates/universe i386 Packages [80.2 kB]
Get:10 http://in.archive.ubuntu.com natty-updates/multiverse i386 Packages [4,267 B]
Ign http://in.archive.ubuntu.com natty-updates/main TranslationIndex
Ign http://security.ubuntu.com natty-security/universe Translation-en
Ign http://in.archive.ubuntu.com natty-updates/multiverse TranslationIndex
Ign http://in.archive.ubuntu.com natty-updates/restricted TranslationIndex
Ign http://in.archive.ubuntu.com natty-updates/universe TranslationIndex
Ign http://in.archive.ubuntu.com natty/main Translation-en_IN
Ign http://in.archive.ubuntu.com natty/main Translation-en
Ign http://in.archive.ubuntu.com natty/multiverse Translation-en_IN
Ign http://in.archive.ubuntu.com natty/multiverse Translation-en
Ign http://in.archive.ubuntu.com natty/restricted Translation-en_IN
Ign http://in.archive.ubuntu.com natty/restricted Translation-en
Ign http://in.archive.ubuntu.com natty/universe Translation-en_IN
Ign http://in.archive.ubuntu.com natty/universe Translation-en
Ign http://in.archive.ubuntu.com natty-updates/main Translation-en_IN
Ign http://in.archive.ubuntu.com natty-updates/main Translation-en
Ign http://in.archive.ubuntu.com natty-updates/multiverse Translation-en_IN
Ign http://in.archive.ubuntu.com natty-updates/multiverse Translation-en
Ign http://in.archive.ubuntu.com natty-updates/restricted Translation-en_IN
Ign http://in.archive.ubuntu.com natty-updates/restricted Translation-en
Ign http://in.archive.ubuntu.com natty-updates/universe Translation-en_IN
Ign http://in.archive.ubuntu.com natty-updates/universe Translation-en
Fetched 520 kB in 24s (21.4 kB/s)
Reading package lists... Error!
E: Encountered a section with no Package: header
E: Problem with MergeList /var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.

see https://answers.launchpad.net/ubuntu/+faq/1591 how to correct that error message.