New
#11
If the PC is new then it's likely not overheating.
I would remove the RAM stick you added to see if the problem continues, and if not then reseat it to see if that resolves it.
If it doesn't then confirm that you precisely spec'd the RAM. You can cross-check using Crucial System Scanner software to find out what type of memory is in your computer. If the specs are even slightly off return the RAM for the correct specs.
If the specs are precise and it can't be made to work correctly after reseating, switching slots, etc., then open a case for troubleshooting or replacement by tech support, or have it replaced by the seller.