O oxygen New member Joined Jun 23, 2013 Posts 2 Jun 23, 2013 #1 Hi all. Sorry for my English. I have serious strange problem. I have two HP DC7800 workstations at home (Windows 7-64bit, e8400, hd6570, 4gb, one 500gb hdd, other 640gb hdd). So, these computers hard working every day 24/7 (photoshop, premiere, outlook, etc.). And..... about month ago i have had very bad surprise. In one hour i get 4 BSOD's from one machine!!! (after that time i don't have any bsod anymore) Scenario: received new email in outlook, answerred. BSOD. restart automatically, loading windows, login- BSOD. restart automatically, loading in safe mode- loading stops at classpnp.sys file. turn computer off- turn computer on- loading normally, but at screen was only mouse cursor in black background. turn off- turn on- finally loaded, everithing fine to the present. 5 days of work without any problems. i have tested memory with Memtest for 20 passes. No errors. i have tested CPU with stress test. No errors. I have checked HDD for errors, everything is good, no errors in SMART too. i don't have any malware or viruses. here is minidump files and some system information: click here. How do you thinking, it was hardware or software bsod's? Thank you wery much.