A repeated failure to open Task Manager —a core Windows troubleshooting utility—strongly suggests the system is compromised and critical tools are being interfered with. In malware-response methodology, Quentin Docter emphasizes that the first step is to “identify and verify the malware symptoms” before proceeding to containment and remediation. If Task Manager cannot be launched at all, that behavior itself is a highly suspicious symptom consistent with malicious activity attempting to prevent the administrator from viewing or stopping processes.

Docter also explains that when systems are compromised by a virus or other malware, the threat agent may embed persistent access methods, and in some cases the only way to be sure it’s fully removed is to reinstall the OS—highlighting how deeply malware can integrate and disrupt normal tools.

The other options do not plausibly block Task Manager: a developer application may increase CPU/RAM usage but typically won’t prevent Task Manager from opening; Windows Update set to manual affects patching behavior; and moving the pagefile can affect performance but not usually stop Task Manager from launching.