An antivirus is utility programming which identifies and expels PC infections. In the event that the product can’t evacuate the infection, it is killed. The antivirus keeps a watch on the functioning of the computer system. If a virus is found it may alert the user, flag the infected program or kill the virus. Some of the common types of viruses are:
Boot Sector Virus: A boot area infection dislodges the boot record and duplicates itself to the boot division i.e. where the program to boot the machine is stored. So first the virus is loaded on to the main memory and then the operating system. Whenever a new disk is inserted the virus copies itself to the new disk. The antivirus overwrites the correct boot record on the infected boot sector and also cleans the bad sectors.
File Virus: A file virus generally attacks executable files. They can join to different areas of the first record, supplant code, fill in open spaces in the code, or make friend documents to work with an executable record. Most of the file viruses are memory resident and wait in the memory until the user runs another program. While another program is running, the virus replicates.
Macro Virus: This infection taints a critical record called normal.dot of MS Word. When the application is opened the infection gets enacted. It damages the formatting of documents and even may not allow editing or saving of documents.
Trojan Horse: It is a code generally hidden in games or spreadsheets. Since they are hidden, the program seems to function as the user wants but actually it is destroying the program. A Trojan horse does not require a host program to embed itself. It is a complete program. Its main objective is to cause harm to the data. They can create bad sectors on the disk, destroy file allocation tables and cause the system to hang.
Worm: Worm is a program capable of replicating itself on a computer network. A worm also does not require a host as it is a self contained program. They generally travel from one computer to another across communication links on a network. They generally disrupt routine services.