My system could not turn on again please help expert?

-my elder brother was using the internet this morning and according to him he said a pop came in demand him to download which he did click the information to download and immediately the system went off and could not power on again please helpHe might of downloaded a virus or a bug that could of corrupted your computer or he could of download a thing called hard drive i don't know the other information with the download but my computer do a thing where i word come on but go to blue screen of death. . Or your computer is dead if its a laptop if not then your prob going to have to take it to a computer store to have them take a look at it. .I think this is not a big issue. Just do one thing remove hard drive and dvd rom and try to switch on pc may be it will work again and also remove the battery from the PC and also do jumper reset.
try switching on and off the power switch on the power supply