Hello, This is a very disturbing issue on my computer. Here's the whole story: I've brought a new computer two years ago. It worked fine until a year later. This error message kept on showing and I've tried most way to eliminate this problem and finally I've found out that replacing my graphic card would make my computer fine. I borrowed another graphic card (7600GS) from a friend of mine temporarily and took the card to repair. They gave me a new card of the same model a month later and it worked fine on my computer except few crashes of the same problem occurs sometimes. But recently, the problem started to show again with frequent crashes, so I suspected this as a problem of VRAM so I've done a test on it using a software called "Video Memory stress Test v1.7" but it told me that the VRAM worked fine. My computer always crashes after logging into windows and shows the BSOD of Page fault in non paged area.The stop code is always something like 0x00000050 (0x"b3b46"138, 0x00000000, 0x8052c8e0, 0x00000000) with only the quoted part changing. Sometimes I can log in and use the computer normally after about 3-4 reboots. I'm running Kaspersky Internet Security 6.0 with updates. I've also updated my Graphic card driver to the newest one from nvidia's website. Temperatures of most components are okay. I've uploaded minidumps of different crashing occasions and dxdiag. Thanks for helping.