'October 2013 Update For Root Certificate for Windows XP ' KB 931125 Installed

Why is it odd!? I am in Canada and our modems are black boxes that have 3 ports at the back (To connect to the power supply, to connect to the wall outlet, and to connect to the computer's ethernet port) and there are green buttons on the front.

After XP Support ends, even though you recommend not unplugging anything and leaving the cable modem on, is the computer still connected to the Internet when the computer is shut down and should it be left on or turned off? 

PA Bear seems to state that the modem 'is' still connected even when the computer is turned off but above you stated that the modem is no longer connected-Which is it?

Does Firefox 28 have the orange, oblong button in the top left corner in order to toggle the text links on? When I press ALT, it just highlights the 'File' option.

By unchecking clearing cookies on exit in the submenu, I assume you mean 'Privacy, History, Settings' and uncheck 'Cookies' under History-It is not worded as 'clearing Cookies on exit' but as 'When I quit Firefox it should automatically clear-Cookies.'

I will be clearer in what I am asking:

There is a black wire that connects from the back of the cable modem to the computer power supply and then the wire connects and is plugged into the power bar.

There is a white cable that connects the back of the cable modem and the wall outlet.

There is a grey cable with a jack on each end that connects the back of the cable modem to the Ethernet port at the back of the computer.

What part(s) of each wire/cable should be unplugged once the computer is turned off?

I do not use Cookie Manager or any equivalent-Should that option be checked or unchecked?

Sounds like an odd kind of setup. In that situation, I would tend to leave things as they are, that is to say, don't unplug anything.

As regards cookies, leave it checkmarked if you're not going to use a cookie manager. In the submenu, uncheck clearing cookies on exit.

When a computer is shut down and turned off but the cable modem is left on, is the computer still connected to the Internet?

Is your phone still connected after you hang up? [Can you still talk to somebody after you're hung up?]

Is your TV still connected when you turn off your cable box & the TV? [Can you still watch a programme after you turn off the cable box & the TV?]

I will be clearer in what I am asking:

There is a black wire that connects from the back of the cable modem to the computer power supply and then the wire connects and is plugged into the power bar.

There is a white cable that connects the back of the cable modem and the wall outlet.

There is a grey cable with a jack on each end that connects the back of the cable modem to the Ethernet port at the back of the computer.

What part(s) of each wire/cable should be unplugged once the computer is turned off?

I do not use Cookie Manager or any equivalent-Should that option be checked or unchecked?

Is it only necessary to remove the power cord from the back of the modem to turn it off or should the ethernet cable (that connects to the back of the cable modem) and the cable that connects to the cable modem (the other end connects to the wall) be disconnected too?

I am using Firefox 28 and the top left corner shows an orange and blue globe icon. When Alt is pressed, it only highlights the word 'File' that is displayed on the top of the screen-Does this version allows the text links to be 'toggled?'

In the 1st screenshot, should the 'Remember search and form history' and 'Accept cookies from sites' be checked or unchecked?

In the 2nd screenshot, should 'Browsing and download history' and active logins,' and 'Form and search history' options be checked or unchecked?

Remove the power cord from the PC, not the modem. You can leave that running.

As regards "Remember search and form history", that's up to you. See here for more info on what those settings do: Firefox Privacy panel

Same goes for the submenu: Remove recent browsing, search and download history

My own settings are those you see in the screenshots.As regards Cookies, I have that unchecked  because I use this Cookie Manager