Help me understand what has happened, please. [View all]

[Paper Roses]

Yesterday AM, as I turned off the computer, I was instructed to let it do an automatic update.
Fine
I run Windows XP SP3, Firefox is my browser. Google my home page.

This AM, when I turned the computer on, my home page looks the same but when I click on any of my 'bookmarks, like DU', the top of my screen is totally different. The home page and bookmarks are now on the right hand side, The tool bar(?) at the top is different. I seem to be missing a whole row of stuff.

Since I am a total idiot on this machine, I have no idea what has happened. I would like to have things back to the way they were but have no idea what to do or what to call the situation.

Can anyone help this old lady get back to normal?

I even did a 'system restore' thinking that I did something and messed stuff up. Everything was just the same after that.

What would cause my active screen to change itself?
It is not the Google home page that is different, just all the bookmarked pages .

And...while we are at it, Microsoft Word will now only print in the tiniest font. No matter what size I indicate, the print comes out about as small as possible.

I wish I was more computer literate in order to explain my recent situation but I don't know the proper terminology.
Any ideas?