Virus removal methods

Boot viruses.

These viruses infect boot records in hard disks by copying it elsewhere on the disk or overwriting it. When the computer loads the operating system through infected boot records the viruses also load into the memory.

Program viruses

These viruses infect executable program files and when these files are executed or loaded in memory, the viruses start making copies of itself and infecting other files on the disk.

Multipartite viruses

Having the characteristics of both the boot and program viruses, these viruses infect multiple different targets. After infecting the program files they infect the boot records when the infected files are executed. As the infected boot records are loaded in memory the viruses start infecting other program files.

Stealth viruses

In a bid to avoid detection, these viruses adopt certain mechanism. They intercept the anti-virus software’s request to the operating system to read the file, thereby avoiding detection.

Polymorphic viruses

These viruses can encrypt their code in different ways so that it appears differently in each infection. They have no identical parts between different infections, which make it very difficult to detect them.

Metamorphic viruses

These viruses avoid detection by rewriting themselves completely each time they are to infect new executables.

Macro Viruses

These viruses infect the macros within a document or template. Some software applications allow macro programs to be embedded in documents. These viruses exploit this mechanism to spread.