Replaced battery, now will not turn on

Everything work, however, battery bulge. Ordered complete kit from ifixit for battery replacement. Turned unit off and followed instructions to remove battery. Replaced with new, supplied battery. Unit will NOT power up (have it connected to a computer). Screen flashes once after pressing power button, and phone vibrates once. No other symptoms. Computer does NOT "see" the phone (like it does if the phone is booted).