My pc crashes..help!!?

My pc crashes while i was playing dota 2. All of the components except cpu and ram are few months old. I kept using my old cpu and ram which are i5 4460 3.2 ghz and 2x4gb kingston ddr3 1600mhz. My mobo is msi h81m-p33 my gpu is asrock rx 570 8gb phantom gaming psu is thermaltake lite 650w. I installed 2hdd and 2 ssd. My pc was running perfectly throughout these months.Today suddently my pc started to crash while playing dota 2. it crashes randomly. when i unplugged and turn my pc back on the system boots normally to desktop. the windows is windows 10 home premium 64 bits and all the drivers were updated to latest version. IDK what is causing this problem. I rebooted and here let the system stay at idle and it kept running without crashing for too long. I have not tested other games yet. but while playing dota  it crashed!! help!