IIRC- the USB from the PC cannot provide more than 500mA
if that is the case, power does not jump out as the issue.
that said, as a test, REM out the high power draw heater and try it with the other sensors.
just to eliminate that possibility.
can you post a photo of your set-up?
Also, others have mentioned how to post code. please visit 'how to use this forum' it is a sticky-post on the top of every forum. Item #7 shows to to use 'code tags' to post code.