Hi just been given a pc that has the above happening. Done a google on the subject and it seems to point to either the mobo or the HDD or the last installed driver. But I can do a system restore to the 28th of october and it works fine for a couple of reboots then it does the same thing. I ran the inbuilt check system the pc has and it didnt find any issues with hardware. I have avast running, malwarebytes running and have run rkill.exe all with nothing found. The PC is only 2 years old. There has been no new installs of any software or drivers, and the owner says it was closed down 2 nights ago and took 15 minutes or so to shut down. and since then it has started up once ok then locked up and started displaying the fault. Im quite happy to back up the customers files and do a full reinstall as a last resort, but if it then happens again I need to be able to tell him what if anything is faulty. Edit just found a thread that says avast can cause the issue, this would make sense as it auto updates after the system restore. im going to disable avast for now and see if it clears the issue. Edit So I ran safemode and disable avast as a service, and the pc booted up fine. BUT...when it loads the desktop and the starts to load the various things in the system tray the desktop flickers and then it starts again building the system tray icons. reenabling the avast service causes the issue to return so this is most definate the culprit. Im going to do a system restore and uninstall avast. back soon Ok so I uninstalled Avast, and it still does the same thing... next was to do a restore and then untick all the startup items in msconfig, this should ensure what ever is causing the failure to clear, but nope, all items unticked and its still doing the same thing. Im now starting a backup of the customers data in preparation for a reinstall.