My laptop will not start up

[Thefailedender]

I was on my Lenovo laptop downloading a game and also playing a game and then suddenly my PC shuts down and I can't turn it on no matter how long I leave it for it just won't start up. Please may someone help i don't know what has happened
Lenovo laptop
8GB ram
1tb
gtx 820m

 

[ffg7]

I don't know as depends on what is wrong with yours & if it can be fixed quickly or cheaply.