finding authentication password

[Guest]

I recently installed Kubuntu on my laptop.
Somehow a password has been created that is required to do system updates and other functions.
I have tried every password that I have used in the past 2 years and none is correct.
Is there anyway to recover this password except by uninstalling Kubuntu and trying again?

[Snowhog]

It's the password you set for your username when you installed Kubuntu.

[Guest]

I gather that, but I don't know what that is. Is there a way to discover it without uninstalling and reinstalling Kubuntu?
If I use the terminal can I change the password?

[Snowhog]

See How do I reset a lost administrative password?