Unable to install softwares from Ubuntu Software Centre in Lucid Lynx
 

I am using Ubuntu 10.04 , but after updating ubuntu using update manager, I am unable to install software using software Centre.When I click install button the software centre does nothing. Update manager concluded
without errors. any help appreciated.

Was this an upgrade from a previous version of Ubuntu? And if so, what version?
Are you able to install software from Synaptic Package Manager, or using apt-get from the terminal?
What is the output of:
http://packages.ubuntu.com/lucid/gkrellm
Gkrellm is a light weight system monitor that I use all the time.

Also, can you post your /etc/apt/sources.list file.

And welcome to the LQ forums!

For Lucid, and all LTS releases of Ubuntu, I always found that a fresh install works best. The distro upgrade thing never really worked out well for me, except on Debian. Then again, I have a forbidden brand of computer: Whitebox (as in built by me with a bare-bones kit)

I installed Ubuntu 10.04 from installation disk , by update I actually mean upgrade of normal software modules , not the complete operating systems.

Are you able to update software using the Update Manager: System > Administration > Update Manager?
What happens when you try to update software using apt-get from the terminal? Try running:
in the terminal. Those commands should update / upgrade all software on your system to the latest updates on the Ubuntu repositories. The Update Manager is simply a graphical front end for those apt-get commands.