Carol, Due to your zone you can't just fill in with concrete it will crack apart and heave in the Winter. You would have to excavate the pathway to the recommended depth in your area. Mine is about 6" then put down a weed barrier then stones for drainage or a bed of sand depends on the soil in your area then you reset your blocks.
Can you just reset your patio blocks? Dig them up and fill in under them with soil to level them. That would be the easiest fix.
There are also plants called steppables. I believe their low growing herbs and when you walk on them the scent of the herb fills the air. You could plant them around your blocks to fill in. Billie

Thank you Billie,
That's what I was affraid of.
Ya, I can redo them,just didn't want to :0)
Even if I palnt steepables, weeds will still grow in between,so, i guess i will re-do them in the spring.Thank you,
Carol