TIP: If you're a Windows XP user, it's possible that the CTRL+ALT+DELETE window is open but just invisible (don't ask why). So if you blindly type the keystrokes that would make Task Manager close the game, that may save you a hard restart. Here's how:

1. Hit CTRL+ALT+DELETE. If a window doesn't appear after a few seconds, then continue.

The window's first two tabs have important lists on it, as seen below...

Applications (1st tab)

Processes (2nd tab)

Notice both have "End" buttons, and have Battlefield listed.

2. I'll hit ALT+E, ALT+E again, then ALT+Y.

That's ALT+E (presses the End Task / Process button), then ALT+E again ("End Task" button in case we're at the Applications tab and it showed a confirmation message), then ALT+Y ("Yes" button in case we're at the Process tab and it showed a confirmation message).

3. If there's no response, maybe we're blindly at the wrong tab. In that case, I'll press CTRL+TAB to go forward a tab, and repeat the Step 2 keystrokes.

4. Considering there's only 5 tabs, repeat step3 up to 5 times, so you've gone through all the tabs.

5. Still not working? Hit the Reset button on your computer (newer computers sometimes need you to hold the Power button to restart).

Despite your initial instincts, the computer will wake right up just fine... you'll have lost any unsaved data (of course), but research online shows that it doesn't corrupt Windows or similar. It's more annoying than anything.

Hope this helps!