My broadband connection is OK !, but Firefox showing me message after browsing "If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web"
and with Terminal not connected via internet, If I try command :~ sudo apt-get update then failed to internet connection, show this image screenshot .How I can solve this ?
It seems your repository settings have some problems.
Run /usr/bin/software-sources.
This program configures package repository.
You can see 'Additional repositories' tab. You can uncheck 'cdrom:[Linux' after clicking that tab to avoid "CD-ROM" message. Then, choose 'Official repositories' tab. And choose proper 'Mirrors' with labled 'Main' and 'Base'.
After choosing, click 'Udate the cache' button or run 'sudo apt-get update' in terminal.
I don't know for certain if this would interfere with updates or not, but immediately I can see that the repeating error is caused by having your update repositories set to include the original installation cd-rom.
To correct please open your Update Manager. Click on the SETTINGS button, click on the left most tab "Ubuntu Software" and uncheck the box next to "Cdrom with Ubuntu".
On the other hand simply placing the original installation cd in your drive could solve the problem, but it could prove inconvenient in the future.