Let's see what you supplied. Not much. I'll have to agree with your friend's diagnosis because they seem to have more details about your PC.
My computer screen keep flickering. Sometime l left it for like 1hr on idle then my screen shows no signal but my cpu is running. My friend told me that it is my graphic card going to be broken soon. Is it true? Anyone help me with this? By the way, l am not very familiar with computer. Please guide me thank you!