Hi, I have just drained all the water out of my water tank and hot water boiler and refilled it, but now I have no water upstairs at all plus no hot water down stairs? Please help!!

Did you open the shut off valve to the water heater?

If you did open the shut off valve do you have water flowing from the hot side but not hot, check if your water heater is on if not turn on your water heater if you have problem check if the pilot is on, let us know, Thanks.

John