PC problem?

It all started when i was playing F.E.A.R, for the first time. I had just got the game today. Started playing it, then i noticed that right at the beginning, there were strips of data on the characters. Then i thought 'its notthing'. Then on characters, these black ugly polygon lines started stretching out from them. And on my weapon, was a little mix of colours. Once again,thought nothing of it. Started playing the game, I did tweak the resolution a bit, to lower coz i thought tat might fix the problem, it made no change. apart from there was no data strips. then mre bits of DATA had shown up, this time on doors and in the sky. The light from lamps would show up with these stringy, type lines, just like a fishing net, but in white lines. Then right at the end, the problem got even worse, the characters soon became engulfed by these ugly polygon like lines.I then realised there was a problem. I shut it down. Then my monitor was flickering every second.