SOLVED
After removing the CMOS battery in addition to the main battery, and powering the laptop on it worked. After, I readded both batteries and it now continues working. Maybe I should replace both batteries to avoid that happening again in the future?
Thank you very much for your support!
Yesterday I was using my Lenovo Ideapad laptop until the screen went totally black, but it was still on as the led’s light was on. 1 or 2 minutes gone by with me trying to press keys for brightness etc, and then it suddenly shutdown. Afterwards trying to turn it on again, the led will bright for 2 seconds until it shuts itself down…
I tried removing and putting the battery again to no luck.
First I thought it could be the CPU/iGPU, now maybe the battery or motherboard is the issue? I repaired this latop many times, but this is the first time this happens, so I don’t know what it can be…
Apart from an old and low-end smartphone I’m using to write this, this is the only computer I own.
Try removing the battery, then with the battery removed press the power on button on and off for about 30 seconds, put battery back in and see if it starts charging.