How Do I Unlock My Samsung laptop Keyboard?

[cjs12345]

Just had this occur for the first time tonight (Samsung Series 9 laptop, bought 3/2013). Couldn't type any characters and when I hit the backspace key I got a symbol. Ran virus and pest scans which found nothing. It started working a short time later and I found this site so I would know what to try if it happens again. I didn't want to reboot in case I couldn't type my PW to get back in! Checked ease of access and deselected the only item selected (turn on toggle key after holding num lock down for 5 seconds). I don't even see a num lock key, only a Fn Lock; however, there is a key I just noticed (duh) and I don't know what it is--to the right of the space bar, between Alt and Ctrl. It looks like a file cabinet and has an arrow on it (like I said, duh).

Glad the keyboard started working for whatever reason; removing the battery is not an option on this model.