Widget text box not opening!

where do I access this database??

Ask your hosts.

And how do I restore it to the website?

It doesn’t need restoring. Why do you think it does?

Ok I’ve accessed it, but i still don’t understand what i need to do with it!
As I’ve said, the widget box has disappeared now after changing to the twenty eleven theme, and so this is why i think it needs restoring! I’m really worried about updating the wp as it’s advising me as i might lose everything! The info in the file manager index.php is the current one, i.e. with the missing info, so obviously these files are not saves but just update as the site changes!

i still don’t understand what i need to do with it!

You do not need to do anything with your database. Just leave it alone!

this is why i think it needs restoring

Highly improbable. The widget box disappeared because you changed themes. Widgets are stored on a per-theme basis.

it’s advising me as i might lose everything!

No. The notice advises you to backup your database before upgrading just in case there is an upgrade problem. With thousands of upgrades happening every day, it’s not surprising that 1 or 2 fail to fully complete. Backing up before an upgrade is just Good Practice ™.

The info in the file manager index.php is the current one

Current what?

obviously these files are not saves but just update as the site changes!

Obviously, you really do have no idea how WordPress works. It does not save your site’s content or settings in files! Take it from someone who has been working with, and developing in, WordPress for over 7 years. Before you go any further, I strongly advise you to read WordPress_Semantics so that you get an overview of the CMS that you are using.

“The info in the file manager index.php is the current one

Current what?”

What I meant is that in this file, the site appears as it appears now after the theme change; with the missing widget box.

You tell me to do nothing with my database and then you advise it IS a good idea to back them up. ?

Basically, my question is, if I do a wp update now, will my site be saved as it is or will I have to rebuild the whole thing?
Meanwhile, the original problem is not resolved, nothing in wp is responding, I am unable to access any content.

You tell me to do nothing with my database and then you advise it IS a good idea to back them up. ?

Yes.

will my site be saved as it is

In 99.99% of cases, the site will be saved as it is.

I am unable to access any content.

Then you have a pre-existing problem that an upgrade may not correct. Try:
– switching to the Twenty Eleven theme by renaming your current theme’s folder in wp-content/themes and adding “-old” to the end of the folder name using FTP or whatever file management application your host provides.

– resetting the plugins folder by FTP or phpMyAdmin.

– re-uploading all files & folders – except the wp-content folder – from a fresh download of WordPress 3.2.1.