Every day when I first turn on my PC I get BSODs with different error messages. Windows won't start unless I turn off and then turn on again my PC. Can you please help me find out why do I get the BSOD errors? Most frequent errors are 0x19 (BAD_POOL_HEADER), 0x3B (SYSTEM_SERVICE_EXCEPTION) and 0x7E. PC specifications: OS: Windows 7 Ultimate x64 SP1 CPU: AMD Athlon II x4 640 GPU: NVIDIA GeForce 210 1GB Mobo: Gigabyte M52LT-D3 Memory: 1x 2GB DDR3 1333Mhz HDD: WD1002FAEX (SATA) PSU: 550W When I first started my PC today, I tried to run memtest86+ and Windows Memory Diagnostics Tool. Windows Memory Diagnostics Tool reported: Hardware problem were detected. memtest86 did not run... I don't know why. After I turned my PC on and off (from ACPI power button, restart has no effect), I let memtest86 run for about 5 hours(see picture for results). Chipset and video drivers are up to date.