New Monitor - problems with horizontal, ie blinking/shaky

Hello all,

My monitor blew out, and I just bought a new one, a Samsung LCD. Vertically, everything's fine, but when I navigate left to right or vice versa, it shakes and blinks. My old one, which was not an LCD, had a slightly jerky motion when going horizontally, but it was not as severe, ie, it was not shaking or blinking, and therefore, was much easier to read. Looks like this needs to be returned, but just wanted to know if anyone else has experienced this problem? Someone on another site suggested it may not be the fault of the monitor, but that it could be a video card problem. Any ideas? Thanks.