Turn my pc on and

Question

turn my pc on and it starts - i can hear fans etc workingbut the problem is my sreen doesnt come on, it says no signal.this is a problem with the pc not the sreen since i have tryed my downstairs pc sreen and it said the sameim uesing a m1100 acer do u anything tip on how to slove this problem would be great.(my mate said i need a new prosseser since mine is not working fully if this is true where can i buy just the prosser)