Replaced battery, now with adapter, no power, no display.

Just replaced the battery. When old battery(swollen, will not charge) is plugged in, MagSafe stays green. When new battery is in, MagSafe stays orange. Always, no display, no power. I just used the computer two days ago before the new battery arrived, with power adapter plugged in, with no problems. I am a beginner, so any advice, try and dumb it down for me. Any suggestions?

****update: now the MagSafe is green with the new battery, so it has charged. But there's still no power. No display, no sound. Seems this isn't a battery problem anymore. Any troubleshooting suggestions?