A:
Once plugged in, look at the second row, go to the last button (ON/Standby button) and press it. It would normally turn the boombox on.
Then make sure what you want to use as SOURCE by pressing the SOURCE button next to the last one on the second row.
If for any reason nothing works after more trials, then bring it to a an electronics store (Best Buy, Radio Shack, etc...) and ask a technician there for assistance to check it for you.