I have some components and sensors wired point to point on a board bought from radioshack. They are powered by a power supply right now and the sensors have outputs that connect to the analog pins on the arduino mega 2560. The serial communication works perfectly when the power supply is not on but when I flip the power switch on, the data on the serial port is a bunch of gibberish. When I turn the power supply off, the serial port starts to read normally again. I have fought and fought and fought with this issue and can't for the life of me figure out what is going on. I have tried to disable Auto-reset (didn't work), I've tried holding down reset, removing and replacing usb cable, and then release when I upload and that doesn't work. Sometimes the L light will flash or stay on, sometimes the TX will flash, and rarely will RX flash. I know of no incident where I would have fried any pins or anything of that nature. Any thoughts would be GREATLY appreciated!