My Computer won\'t turn on

[bashir1]

I have a windows vista regular desktop with LCD monitor for the past month it's been shutting off randomly unless i take off the cover and put a small house fan on last night my computer shut off and when i tried to turn it on , it started like usually but my screen was black i can't even see windows logo cursor nothing. please help me. everything seems to be working but my monitor stays green for 5 secs then turns yellow help please.

 

[bashir1]

I can't even acces my computer the screen is black .....