Went into sleep mode and does not start

The laptop was bought less than a month ago and has been working fine until this afternoon.

I turned it on, the screen to enter password appeared before entering password I clicked on the wifi sign on the right lower corner. The password space vanished, but the screen saver photo remained in full screen. I put the lid down because I thought that when I would lift it the password space would re-appear. Instead the lap top went into sleep mode (the light on the right side still blinks) and the screen was black.

I tried to start the computer but nothing happened.

I connected the power cord and plugged it. Still nothing happened and neither the battery light turns on.

I kept the start button pressed for 30'' and tried to restart (with and without plugging in) but still the lap top remains in sleep mode (light is blinking).