user event agent running at full power

i have a 15 inch i7 with 8 gb of ram also it has 250GB storage. i am running the most uptodate operating system when i log on after about 5 min the user event agent runs up to full power and then crashes it. The problem still persists after multiple installs of osx and replacing the hard drive. The computer creates no crash log and does not slow down before it powers off. The genius bar has run hardware diagnostics and prety much told me to go away and that i am running high powered games which are crashing it. i have hearthstone and that is it on that machine. i later removed that and the problem still persisted but. the problem only occurs when i am running programs and not in safe mode. they have installed the ox from a disk image and there is not remnant of the old osx remaining.