Help! Garden path question

swebb

The path at the back of the house (about 10ft x8) is looking a bit depressed. I can blast it with the power hose as there are a few weeds (nothing much though) and put weed killer down to kill off anything left over. However, the path is made of what I can only describe as 'brick looking tiles' (they are brick shaped, but not as deep) and some of these have sunk.

What's the best way to repair these? Take them our and cement them back in? Then cover the whole path with a sealant?

Or something else?

(If I knew how to put a picture on here I'd post one).