See if just opening the task manager and leaving it open also keeps the pc from freezing. If so - that points towards a malware.
Additionally you can set up a monitoring software to get the load readouts on your phone and see if maybe something weird is going on when the pc should be idle (like 100% cpu load or disk usage). Pitikapp + hwinfo is a free combination for such setup.
Does the keyboard numlock button change state when the pc is frozen (led turning on and off when you press it)?
See if just opening the task manager and leaving it open also keeps the pc from freezing. If so - that points towards a malware.
Additionally you can set up a monitoring software to get the load readouts on your phone and see if maybe something weird is going on when the pc should be idle (like 100% cpu load or disk usage). Pitikapp + hwinfo is a free combination for such setup.
Does the keyboard numlock button change state when the pc is frozen (led turning on and off when you press it)?