Which type of virus replaces the targeted program entirely?

The type of virus that replaces the targeted program entirely is known as an overwriting virus. This virus operates by taking the existing file, such as an executable program, and replaces its contents with its own code. As a result, the original program is lost and cannot be recovered, as the overwriting process deletes the content of the original file.

Overwriting viruses can be particularly damaging because they don't just infect a file but completely eliminate what was there before, leading to data loss and rendering the program inoperable. This ability to completely replace a program makes it notably different from other types of viruses, such as companion viruses, which create a new file that works alongside the original without altering it, or document and macro viruses, which primarily target specific file types (like Word documents) and usually do not replace the original files entirely.