Word Home & Student 2013 Won't double space existing text Windows 8.1

If the text has a particular style attached to it, you need to modify the formatting of that style. 

In an existing document, you could select the text and then use CTRL+SHIFT+s to display the Apply Styles dialog and then press the Reapply button, or select the text that you want to be double spaced and then access the Format Paragraph dialog and change the line spacing.

When I press block the text and press CTRL+SHIFT+s it starts uploading to the cloud drive.  I'm really struggling with this.  One thing I have thought about is I probably started some of these documents on a different version of word, can't remember what version though could that be it?

I have pressed CTRL SHIFT  S this time (not CTRL space S) and nothing happens.  I've already tried paragraph formatting and that doesn't work either.  I've tried saving it to earlier versions that doesn't work.  I prefer to write in single spacing then convert to double and have never had any problems till i got word 2013.

It seems that something has happened to your shortcut. Normally, Ctrl+Shift+S should have a specific function within Word (specifically, to display the Apply Styles pane).

If you click the dialog launcher button (the little arrow on the bottom right) in the Styles group on the Home tab, you'll see the Styles pane. Which style do you see in the pane? Which properties are specified if you right-click the style name and click Modify on the context menu?

Also, if you wish, feel free to upload an example document that illustrates the problem to (say) OneDrive or Dropbox and post a link here.