I have encountered this problem several times now when I do a full computer scan. The computer shuts down before finishing. Is there a specific malware connected with this problem?
I had similar to that with a Toshiba laptop. It was overheating which caused it to shut down.
Where I am in France it is 36C today so heat can be a problem.
Checking Windows event logs may show why the system is shutting down.
I agree with JamesFrance overheating is more likely than malware.
If the air intake is on the bottom using a stand or prop can allow more air flow to assist in cooling.
For overheating check/clean air passages, air openings, heat sinks, fans, fan filters, gently using compressed air if possible.
Also check for other conflicting or other malware programs running at the same time causing the system to work harder.