^What he said. It is a characteristic of the graphics card. What graphics card do you have now? If you provide your complete system specs (including the brand and model, not just wattage, of your PSU), and your budget, we can suggest a graphics card for you.
you couldn't download it, like the others two post stated this is apart of graphics card it's not a software to update. So the only way is for you is get new card with pixel shadder 4.1 or high.
man pop fs require pixel shader 3.0 i use swift shader that emulates it but gives me lags glitches and slow speed, is there any gma booster that works for me or any 3D render that emulates pixel shader 3.0 .....pls reply :>