Unity 4.1.2 run without pixel shader

I used to work on unity 3.5 and it worked fine. But now i have downloaded Unity 4.1.2. When i run it , it show me an error that my graphic card does not support pixel shader 2.0. After the error nothing happens and Unity editor DOES NOT OPEN. I may not use pixel shader but is there any way to turn off the pixel shader simulation and run unity. Old version worked fine on my pc without pixel shader. I don't need any kinda pixel shader, just wanna run and use unity as like the Unity 3.5. Is there any way to skip the pixel shader check or to fool the unity editor so that it thinks that there is pixel shader. Please help me solve this issue. Else, I again have to use 3.5 and my 650 MBs of will be wasted.