Hello, i just met a strange problem with my dell vostro 3650. 

Yesterday it started spontaneously - appx. once a two hours- switching in sleep mode (or something similar, screen is black, but fan and HDD is turning and some of the fn buttons are functional - etc. switching wi-fi antena, switching keyboard light, but pushing some others has no effect - etc. switching touchpad. ) from witch it can be recovered only by removing battery. I run OK avg test ("no infection found") and run chkdsk-r. Today it happened again, so I remove battery, put it in and boot  OK again and in fifteen minutes the machine crash totaly - all is dead, and pushing power button has no effect. 

Has someone seen this before?

Thank for reply!