how can i uninstall firefox completely ? and reinstall it again...

  If I had the power I would stop this why so many?????????????
  God give us a chance.

   David
  in TN

@david jones
you would stop what?

@coolmiles

press CTL+ALT+T to get into terminal, then type

sudo apt-get install -purge remove firefox*
sudo apt-get autoclean
sudo apt-get install update
sudo apt-get install upgrade
sudo apt-get install firefox

type your password when asked. it won't show on the screen.

when i use this command,
sudo apt-get install -purge remove firefox*
it shows, "E: Command line option 'p' [from -purge] is not known."
i had done uninstallin and reinstall firefox but still it shows error,
still a'm not able to login to my net-banking site....
so i just want to remove my firefox completely an install it again...

For the first command, I think Marcus meant to say that you should run:

sudo apt-get purge firefox\*

(Or he might have meant "sudo apt-get --purge remove firefox\*", which is equivalent. Either way, apt-get will not recognize the option "-purge" with a single initial hyphen, and specifying both "install" and "remove" operations in the same apt-get command will not work. Also, if you have a file whose name starts with "firefox" in your home directory--or whatever directory you're in when you run this command--then it's necessary to escape the * by prefixing it with a \; and if not, the \ still doesn't do any harm.)

By the way, completely removing and reinstalling Firefox is rarely useful. It's much more likely that your user-specific configuration would be messed up, then systemwide Firefox files. To remove your user-specific configuration (and thus cause a new, clean one to be created next time you run Firefox), close any open Firefox windows and run this command in the Terminal:

mv ~/.mozilla ~/.mozilla.old

If you wish, after running that command and determining that the old configuration was the problem, if you don't have any bookmarks, history, cache, or other personal data that you need to retain, you can run this command to delete the old configuration once and for all:

rm -r ~/.mozilla.old

Alternatively, you can get your old configuration back (which, of course, might re-break Firefox) by running:

rm -r ~/.mozilla; mv ~/.mozilla.old ~/.mozilla

On the other hand, if your problem is with playing videos embedded in websites, then it's probably Flash, rather than Firefox, that you're having trouble with; in that case, please run this command, and post the results here (i.e. the text from the Terminal):

dpkg -l | grep flash; dpkg -l | grep gnash; dpkg -l | grep swf

That command will not actually *do* anything, but the text it produces provides useful diagnostic information for solving Flash problems.

By the way, when you run commands provided by others (for example, here on Launchpad), I recommend copying and pasting them into the Terminal, rather than typing them in, as this significantly decreases the likelihood of entering them incorrectly.

1/2 problem is solved, but now the problem is i'm not able to login to my net-banking site an not able to add an add-ons to firefox,
when i open addons it shows " Firefox couldn't retrive addons"
and i am not using the commands
"mv ~/.mozilla ~/.mozilla.old
rm -r ~/.mozilla.old
rm -r ~/.mozilla; mv ~/.mozilla.old ~/.mozilla
dpkg -l | grep flash; dpkg -l | grep gnash; dpkg -l | grep swf"
so please tell me how to use these commands....

"so please tell me how to use these commands...."

I *did* tell you how to use them. If you have read my detailed explanation of how to use them and you still don't understand, then you'll need to indicate more specifically you are confused about. However, perhaps this will help:

First, to use those commands, make sure you're using the right one of them (or the right more than one of them). They do different things. They will *not* all be suitable. Their function is explained in my previous post.

The first command ("mv ~/.mozilla ~/.mozilla.old") is the one that I suggest you use now. To use it, close any open Firefox windows, paste it into the Terminal, press enter, then reopen Firefox. It is possible that this will fix your problem. This disables you current profile (which contains all your user-specific settings, bookmarks, cache, history, saved passwords, etc.), by renaming it to something that Firefox does not recognize. As a result, Firefox will create a new, clean profile next time it runs. That solves many problems; it might solve yours. If not, please post again.

I think its not a fault of firefox i tried google chrome and the same problem occurs, so please tell me how to solve it,,,,
i am not able to use my net-banking site,
i think its mistake in my system settings,
when i open onlinesbi.com the page gets opened but after entering username and password i'm not able to login...
 site shows me a warning' "The website certificate can not be verified. Do you want to continue?"
and when i select the option " Always trust content from this publisher." and click on RUN even though i m not able to login my account...

I think you will have to provide more information when it comes to the certificates-error.

Last time I had such errors I tried to connect via a UMTS USB-stick and my traffic expired, so my ISP blocked all connections but the one to its own home page where I was asked to buy more traffic. So this may have something to do with your ISP and/or your DNS settings.

when i open any site it shows me the following,
"" This Connection is Untrusted
You have asked Firefox to connect
securely to www.irctc.co.in, but we can't confirm that your connection is

Normally, when you try to connect securely,
sites will present trusted identification to prove that you are
going to the right place. However, this site's identity can't be verified.

What Should I Do?

If you usually connect to
this site without problems, this error could mean that someone is
trying to impersonate the site, and you shouldn't continue.

 Technical Details

www.irctc.co.in uses an invalid security certificate.

The certificate is not trusted because the issuer certificate has expired.
The certificate will not be valid until Thursday 19 August 2010 05:30 AM.

(Error code: sec_error_expired_issuer_certificate)

 I Understand the Risks

If you understand what's going on, you
can tell Firefox to start trusting this site's identification.
Even if you trust the site, this error could mean that someone is
tampering with your connection.

Don't add an exception unless
you know there's a good reason why this site doesn't use trusted identification.""

Whwn i select the above option i understand the risk, it ask me to add exception for that site,
and it happened every time when i open any site....
when i add an exception than the site works properly but after closing browser and come again than again it ask me to add an exception....
all sites work properly except my net-banking site... after adding an exception for that site it shows me the warning message as
"The website certificate can not be verified. Do you want to continue?"
and when i select the option " Always trust content from this publisher." and click on RUN even though i m not able to login my account...

And there is no problem with my ISP settings...

Do you really understand the risk? You have no idea who you have just connected to -- none. Call up your bank and ask them to fix their certificates, or to provide some other method of authentication. If they wont, switch banks.

Anyone could have just taken your money -- Anyone. You just bypassed all the security checks that your machine performs, and you may be either:
1) using a bank that has bad security, and setting yourself up for a crook to steal your cash
2) the victim of a man-in-the-middle attack (https://secure.wikimedia.org/wikipedia/en/wiki/Man-in-the-middle_attack)

These attacks can be automated, so the "why would anyone target me -- I don't have lots of money" argument is invalid, you personally might not have lots of money, but if you pool together thousands, or tens of thousands of you, then the attack becomes economically desirable.

Wait, hang on

>The certificate will not be valid until Thursday 19 August 2010 05:30 AM.

I originally read that as 2011. Is your system clock set to the right time?

but i can access my netbanking a/c from another sytems, so its a fault in my system...
my system was not set at right time but now i set the right time but still i'm not able to log in, after setting time the warning message is not showing but still not able to access

You've set your clock to the right time, but is the time zone also correct?

You said the warning has gone away but you're still "not able to access." Is there some *other* error message? What happens now when you try to access it? Does it still not work *both* in Mozilla Firefox and in Google Chromium?

ya i set the timezone,
now its working in chrome but not in firefox,
after filling user name & password when i click on login than nothing happes, ther is not a error message and the page is stay as it is nothing happen....
btw i can access it from chrome its enough for me.... so its not compulsory for you to solve this fro firefox, if you know how to solve it than tell me otherwise its ok, don't worry dude....
thanx for your help buddy...

thanx buddy....