I have a Lenovo ideapad 310 that won't turn on without a charger plugged in and it's only been a year since I bought it and have been using it ever since. When I remove the AC adapter, the laptop immediately turns off. I am not sure if it's the motherboard or just the battery. The battery is internal and I have also tried holding the power button but it doesnt do anything but power on... I did try holding it for 2 minutes. But No reset thing happening, whatsoever. Please help me.
Sounds like the battery to me. You need a new one.
Yes the battery is internal, and may be hard to get to, but it is replaceable. If the warranty is still on the device (can't hurt to check) then contact the manufacturer about the replacement. If it is no longer covered, then you can either try to do the replacement yourself, or take it to a local tech. Just do consider going with an OEM battery rather than aftermarket. I say this because those are a bit hit or miss.