80 degrees C is very high for an idle processor state. Around 50C is reportedly 'normal' for that processor. Around 80C is probably right for gaming.
1# I would first check your Windows Power Options - Start > Control panel > Hardware and Sound > Power Options > Change plan settings > Change advanced power settings
Extend the option 'Processor power management' and make sure they read exactly as I have mentioned below:
- Minimum processor state is at '5%'
- 'System cooling policy' is set to 'Active' for Battery and Plugged-in. If it says 'Passive', then the system is not using the laptops fan to cool the processor
- Maximum processor state is at '100%'
Once done (if you needed to change any setting), select 'Apply', then 'Ok'. It might ask you to restart your computer. Follow that instructions and once rebooted, check tempertures again.
2# If that does not solve your problems. Ensure the processor heatsink and the cooling fan is seated correctly to the processor. Also, ensure you have used only a half a pea size worth of thermal paste. Applying too much can actually increase temperatures. Finally, use a can of compressed air to blow out the heatsink and fan for the processor. A build up of dust can cause the laptops cooling to become ineffective.
Hope this helps.