Will 120hz monitor fix this?

Solution
What video card are you running, what refresh rate do you have set, and do you have VSync on or off? Also, this the only time you see this in that one game?

Try 60hz for monitor refresh, turn ON Vsync, make sure your video card can handle the game OK to at least 30 FPS, and check it again. You may also watn to check for driver updates and maybe game patches. You should not need to upgrade the monitor to get rid of those artifacts.
What video card are you running, what refresh rate do you have set, and do you have VSync on or off? Also, this the only time you see this in that one game?

Try 60hz for monitor refresh, turn ON Vsync, make sure your video card can handle the game OK to at least 30 FPS, and check it again. You may also watn to check for driver updates and maybe game patches. You should not need to upgrade the monitor to get rid of those artifacts.
 
Solution
Thanks!! Forced VSync with Nvidia control panel and that solved the problem. Much better. I tried turning VSync on with the user.cfg file but it didn't help. I have a GTX460 1Mb by the way. Wasn't sure what tearing was, now I know.