Does it have an actual power switch ?
Sounds like you've got it set on standby.
You need to change that to hibernate, or just switch it on and off properly.
What frequently happens is the battery runs low, the laptop shuts itself down in standby mode and then gets locked into that state.
So that when you switch it back on it still thinks it's in low power standby.
Unplugging and removing the battery resets that.
Which is why that actually works.
And yeah the current trend for sticking the battery inside the shell is bloody annoying.
Hibernate is a much better option, almost as quick, but with the benefit of shutting the power off and saving battery power.
In standby mode, power us still being used.
You still can get the same issue in hibernate mode, but it's much easier to reset and dies not involve taking the machine apart
If you like I can give you a call and we can set up a remote service for it
I do a lot of work via remote support software these days.