forerunner 45 shuts down mid run, 2 years old, latest update installed

My forerunner 45 will not stay on during my runs. The charger stopped working in the summer but has since been replaced and it now fully charges but will not stay on during any of my runs for more than 2.5 k. The latest update is installed and it’s still holding charge, I’ve done a reset. The device is 2 years old.. do they just stop working after 2 years :( ?