Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.
Rootkit:W32/Necurs is a kernel-mode driver component that can be used by an attacker (or added as component to another malicious program) to perform unauthorized actions to take control of an operating system, without alerting the system's security mechanisms.
According to published research, the Necurs rootkit was incorporated in late 2014 into the Gameover Zeus botnet as a protective mechanism, preventing attempts by the user to remove the malware from an infected machine. The addition of the standalone Necurs rootkit to an existing threat operated by another party (and analysis of the rootkit's code, which appears to be suitable for such use) has lead to it being considered 'crimeware for hire'.
More details and commentary about this malware is available at: