Viruses are known to affect any type of file and destroy the data stored in that file. One particular types of viruses  which only affect the executable files and program files are the File Infectors. Their main target are files with EXE and COM extension. Running an infected program means that the payload of virus is executed. This is unarguably the most common type of computer virus. It is also the most damaging virus forms. The malware of this category has caused tremendous amount of damage to computer systems all over the world. It spreads through removable storage as well as over Internet.