No atomizer: Unscrew the atomizer. Screw it back on and when the device displays "New Atomizer?" press the corresponding button for "NO". Also, check the sping loaded 510 pin in the mod is not stuck and the atomizer is screwed in securely.
High Ohms: The supplied coil is rated at .20 ohms. If it is way above that reading, make sure all the pieces of the atomizer make a snug fit and the atomizer is screwed into the mod securely. Disassemble and assemble the atomizer if needed. The coil is actually 2 pieces: an outer casing housing the inner coil itself. Check that the tabs on top are connecting to the coil. At the bottom part in the center there are notches on the coil that make contact with a center pin. This part should be slightly protruding--check that it hasn't been pushed up into the sleeve.