Virus

A self-replicating type of malware that often mimic or attach to legitimate programs and hide inside them. It modifies, backdoors, and/or damages the infected system.

There are different types of viruses.

Boot Sector Virus

This type executes every time the system boots, since it has attached itself to the boot sector. Boot sector viruses move the MBR to a different location so that the virus can execute before the MBR can. They're especially hard to remove since they re-infect the system on boot. The most common solution is to recreate the MBR using the Windows Recovery Console. If that fails, you might want to reinstall the OS.

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