Hello,
Based on my understanding of your issue, I suggest you open the computer in safe mode and use antivirus software to check. Currently, Microsoft has stopped supporting the Windows Server 2012 R2 version of the system on October 10, 2023. For safety reasons, I suggest you upgrade the operating system if possible.
Windows Server 2012 and 2012 R2 reaching end of support - Microsoft Lifecycle | Microsoft Learn
Best Regards
Zunhui