Pavilion DM1-4010us: random shut downs

This has been happening for a while now, where the laptop will go to sleep seemingly at random. There isn't any one action that I can find that causes this. A push of the power button and it wakes up and continues on its way. Other times it will do to sleep but instantly turn itself back on. No data loss, it returns to wherever it was at the time of the shut down.
But this time it shut down and wouldn't wake up. Totally unresponsive, until I removed the battery and tried running the machine off the AC charger. Started up just fine. Put the battery back in and it is working again. Right now it will run off the battery only, while the unit is plugged in and charging, and with the battery removed.
Odd. Any ideas what might be going on??

 

Need more background on this.
1. What O/S are you using?
2. Is this all standard OEM from manufacture no Modded parts?
3. Is charger OEM not 3rd party charger and the same for the battery?
4. Did you check your power settings to make sure it is setup properly?
5. Did you make sure if Windows has the proper updates?
6. Did you make sure the BIOS/UEFI is up to date?

 

1) Windows 7 Pro, SP1
2) Laptop and all parts are OEM. No mods of any kind.
3) Charger and battery are also OEM.
4) Not sure what constitutes "proper" power settings, but I haven't changed them prior to this issue appearing.
5) All Windows updates are installed.
6) BIOS is up to date, also.