wmiprvse.exe is the name of WMI provider host process, so I think you had a false alarm from your antivirus. If it eats a lot of CPU time, try stopping Windows Management Instrumentation service and check whether the problem persists. Note that this will stop Windows Firewall as well.
Of course, a virus could have disguised under that name, but 7-Zip does not contain any malware (if you download it from 7-zip.org or sourceforge.net).
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