How to deal with video card lock ups when gaming

Hello all. I'm not entirely sure, but I believe this is the best place to ask this question.

I'm running my computer with a Nvidia GTS 450, and the main and usually only game I play is World Of Warcraft. I play the game all with pretty low settings, despite my computers ability to run on higher settings. Everyone once in a while, I'll be playing and high resolution Spell will come onto the screen. Sometimes, when this happens, the screen will cease any movement or life for about 3-4 seconds, and then resume playing as normal. Normally, it isn't a big deal but it is something I'd like to fix.

I bought my DS computer on Black Friday, and got a free Video Card overclocking as part of the deal. What I'm wondering, is if the screen lock-ups are due to the video card overheating. The computer also came with a tool called "EVGA Precision" installed on it. When the lock-ups first started happening, I turned down the "Core Clock" and "Shader Clock" significantly (Nearly all the way down) hoping it'd stop the lock-ups. I also turned up the fan to about 75% capacity, which brings the GPU temperature to ~43 Degrees Celcius on a normal night.

I've also made sure to download the newest driver available for the 450 GTS. The next step I was going to take was putting a desk fan next to the computer case and running it while I game. What I'm asking, is if there is anything else I could do to prevent the lock-ups from happening, if that is even 100% possible.

43C is absurdedly cool for a GPU, but your problem lies with your higher settings than your rig can handle. A GTS 450 is fairly low end of graphics, and it'll bottleneck your system if you're running an i7 9 series like I hope you might be. High is not the setting for your GPU, try med or low?