My machine (i7 based + 16GB RAM) randomly locks up after a few hours where the on-board HDMI port just stops displaying the screen and just switches to random pattern. I lose mouse and keyboard and there seems to be no HDD activity. Looks like the computer is just locked up.
Here is some of the testing I have done
1) memtest 86+ shows 0 errors for an 8 hr test duration
2) intel HW monitor utilty shows good airflow and CPU temp and voltages
3) I can get the same lock up EVEN if I do not log into windows at startup and just let it sit at the login window
4) I do not need to have any activity or application running on the computer
I looked at the event log and there seem to be critical power event but I suspect that was due to me holdinghte power button to reboot the system when this event occured.
Now i have reset the log and will run this again.
"You try to enable kernel dumps \ change the restart option for a blue screen."
>> I do not know how to do this?
"if you suspect the video card: it there a way to replace it temp to ensure that the card is the problem."
>> I am using the on-board video via HDMI port. There are no cards installed. It is surprising to crash in this manner since I do not get a frozen screen or a ble screen I just get a lot of horizontal/vertical lines and boxes (kind of like when you are testing the video output of a card going thru various patterns).