Sorry to trouble you folk. I have been struggling with this problem for about a month. I have done all the things I know/understand and I am getting nowhere. My computer closes down once a day - always within 2 hours of turning it on. After that it is fine and goes all day and into the early hours of the morning with no problem whatsoever. The minidump files all seem to indicate the same problem (to me anyway) I have installed new ram. New keyboard, changed the mouse. Unplugged external hard drive and webcam. Cleaned the fans. I have Run the system diagnostic report and the lights are all green. Only problem being reported is that it is not detecting an antivirus although I do have AVG installed and working. I have run the HP diagnostic tests and everything passes. HP SG3-230UK, Win 7, 64bit. 8gb ddr3 Crucial ram (new) Using the BlueScreenView is indicating it is caused by hal.dll but I don't know how to interpret this any further. I would really appreciate any help anyone can give. I will upload anything else you might need if you let me know. Thanks.