Brower installations on latest Ubuntu Desktop version

[Gins]

Hi
I am new to Ubuntu. I used Ubuntu some 4 or 5 years ago.
I have installed the latest Ubuntu to my desktop computer which has an AMD 64 bit processor. I installed it this morning.
There is a problem with Firefox browser.
I can't install it.


There is an icon called 'Mozilla Firefox Browser installer'. When I click it I get the following error message.

…................................................. .................................................. ...................
Another application seems to be using the package system at this time. You must close all other package managers before you will be able to install or remove any packages.
…................................................. .................................................. ......................
I don't how to solve the problem.
Please help me.
…................................................. .................................................. .......................

I downloaded the Opera browser. How do I install it. If it is a 'tar.gz' , I know how to install it

opera_11.61.1250_amd64.deb

Please help me.

[cespinal]

Hi Gins. Don't worry. There is nothing wrong with your system.

Close all the programmes that you have open. One of them -maybe the software centre or synaptic- is still working and not allowing you to download packages.

I think ubuntu comes with firefox by default. Anyway, if you are using ubuntu, click on the dash icon and type software centre. open up the software centre and look for whatever browser you want. Opera should be there as well.

To install a deb file you just need to click on it....

[Gins]

Thanks Cespinal for taking time to reply me.

I can't find any open program.
How do I find open programs.
It seems there are no open programs

Ubuntu comes with unknown browser called rekonq. I am totally unfamiliar with it.
I need firefox.

I can clearly see on the bar about programs which are running or rather open. There is nothing.

[Gins]

I beg Cespinal or other experts to help me. To go to the Internet I need a working browser.
So please help me.