I have bought a new hardware recently ( Asus M4A78LT-M LE, AMD II X3 440 and Geil 2GB DDR3 1333 Value 9-9-9 ) I assembled everything togheter with hardware left from my old PC, which gave me this: CPU: AMD II X3 440 Mainboard: Asus M4A78LT-M LE Memory: Geil 2GB DDR3 1333 Value 9-9-9 Hard Drive: 160 GB Westgate Video: Geforce 9600 GT Power Supply: Chieftec smart 450W I formatted whole HDD and installed fresh copy of Windows XP service pack 2. After few hours my windows started crashing ( BSOD, PAGE_ FAULT_IN_NONPAGED_AREA, STOP: 0x00000050, nv4.disp.dll, dumps of the BSOD in the attachment ) when I tried to play Crysis or Race Driver Grid. I checked other games and windows crash in all of them ( Modern Warfare 2, Need For Speed Shift, Left 4 Dead 2 ) with same BSOD. I tried reinstalling GPU drivers but that didn't helped, I also tried installing old ones, no success. I have noticed that almost all of my applications suddenly crash ( Mozilla, Chrome, Office ) after few minutes of use. Furthermore, the files I download from the internet or copied from the usb sticks to HDD gets corrupted by CRC errors very often I reinstalled system two times but that didn't solved crashing and BSODS. After that I had all my hardware component tested and I also have found nothing: CPU: Tested with orthos ( I ran two instances to test first two cores and the third one ) One hour test with no errors. ( 35 - 38 C when IDLE, 45 - 48 C when in stress ) RAM: I tested my stick with Memtest86+ 4.11, 13 passes and 7 hour of testing which gave me no errors. I tried testing them with this Memtest from hcidesign.com it gave me few errors but I find Memtest86+ to be more reliable. ( Maybe I'm wrong? ) HDD: Tested with HD tune, CHKDSK and HDD Scan 3.3, no errors. ( 38 C - 50 C ) GPU: Couldn't test because system crash when I try to run any graphic advanced application or game but it was fine before I changed my hardware. ( 55 C in IDLE and up to 70 C in stress ) Here's my question, what should I do? I'm getting out of ideas. At start I thought that all errors are caused by bad stick of RAM but Memtest86+ didn't showed any errors, which made me confused. Thanks for the help, I'll provide you with all information you'll need, just tell me. Any kind of advice will be appreciated.