The control key does work. It just doesn't work the way that it works in Windows. That is because Android is NOT Windows and never will be. Not saying that some bright programmer won't build in some standard windows key functions, but it presently isn't there.
You can select all text by doing it the Android way....touch and hold on the screen until the menu pops up and then select "Page". On the resulting menu is Select Text. Tap that and then drag your stylus through the text you want to select. Not what you are used to in Windows, for sure, but again.....this isn't Windows.