PC - Shooting Game

Hi, there's this PC game that I have been looking for.
I think it's an FPS game where you have to fight you're way till the end.
I couldn't elaborate more, since I only played this once.
If you have any idea what game is this, please let me know.
Any guess would be appreciated. Thank you.

I think I know which one you mean, its the one with the guns isn't it?

100% actually

Try and help bit more. When is the game set? Medieval times, modern day, Sci-Fi (in space)? What weapons do you have? Swords and arrows or guns and rocket launcher's?

does this game have buildings?

sorry guys. this game uses guns & grenades. Ahm, it's got buildings (i think). LOL.
I think the name has 4 or 5 letters. so sorry for making things hard. LOL

Ok, when you played it was it new (a year or two) or was it old? Also when did you last play it.

4 letter, guns, FPS, involves fighting all the way to end.....

Guess: FEAR

DOOM

Doom, Doom 2, Doom 3 ?

left 4 dead