What steps do I take when I just got an check engine light code PO442 on my 2007 chevy hhr

Are you having a hard time starting the vehicle? There have been problems with the electrical system but GM also recommends an update for the Engine Control Module (ECM).
P0442 normally indicates a small leak in the Evaporative Emissions Sysytem (EVAP) that could be as simple as a worn fuel fill cap gasket not sealing properly.
Check or just replace the gasket on the fuel cap and make certain it is tightened after each fuel fill.