Laptop Power LED Indicator Blinking/Flashing

I have an ASUS K40IJ laptop. It's battery has long worn out so I'm just using it without its
battery, using the charger as its power source. It's CMOS battery also had worn out recently
and the only problem with that is as soon as I plug in the charger into it, it automatically
turns on, and I have to set the time and date everytime I use it. I have read that its
normal since the CMOS battery isn't working anymore. I have been using it without any other
problems ever since. I didn't run into any problems when I used it last night either. But
earlier today, after plugging it's charger into it, it didn't turned on automatically as I
was expecting. Instead, the LED indicator in the power button and the one for it's screen
kept blinking/flashing while the other one in the charger and the one for it's hard drive
didn't. I have tried plugging it out of its charger and pressing the power button for
several seconds to drain all the remaining current, as I have read in other forums, but it
also didn't work. What should I do?