Computer Virus accounts for about 7% of total data loss

Computer Viruses : Cause of Data Loss

Another threat to your important information is posed by a computer virus. It is a synthetic self-replicating computer program that spreads by infecting the documents and files.

Since, worms and viruses have increased in number in the recent years, This accounts for about 7% of total data loss.

The three main types of viruses, which are responsible for maximum amount of data loss, are:

• Boot Sector Viruses / Boot block Virus / Boot Virus:

It is a type of computer virus that infects the first or first few sectors of the hard disk or floppy disk, which allows the activation of virus as the diskette or drive boots.

What boot sector virus does ?

Boot sector virus infects computer systems by infecting it own code either to the partition table on a hard disk or the boot sector on a floppy disk. When the system boots from the hard disk or diskettes, virus is executed and installs its own code in the system’s memory. The Boot virus can spread to every disk that the system reads through the memory. These viruses are the most common of all other viruses. The examples of boot viruses are Stoned virus, Michelangelo, Disk Killer, Form, Junkie Virus, and Ohio Virus.

Symptoms ?

A boot sector virus may cause several problems relating to boot or data retrieval. There are cases when the data disappears from entire partitions or the computer suddenly becomes unstable. The failure to startup or to find the hard drive are the common problems that can be noticed when the virus attacks a system.

You may receive an error message on startup saying, "Bad or missing command interpreter. Enter name of command interpreter."

How it spreads ?

When the system boots or is attempting to boot, boot sector viruses are spread to computer systems, from an infected floppy disk. Any disk, even if it is non bootable can cause transmit the virus into memory, if it is in the drive while the system is booting up. The virus can also be spread across networks, if you are downloading files or trying to open up an email attachment.

Precautions

In order to keep your system and data safe from virus attack, the following tips can prove to be of some help.

• Make sure that you install virus detection software on your computer. Anti-virus programs perform the following functions in order to keep your system safe from the virus attack. Scan for viruses on disks and if found would remove them.

• File infecting viruses / Program viruses:

This virus infects executable program files by adding its own code to the executable file. When you run an infected file, the virus can attach itself to other executable files. The files that are infected by this type of virus are usually with extensions like .COM, .EXE, .SYS (device driver).

Overlay (.OVL) files and Dynamic link library (DLL) files are the file-infecting viruses that are designed for specific program. These are non-executable but are called as executable. The virus becomes active in memory when an infected file is executed. It makes copies of itself and infects files on disk.

Sunday, Cascade, Nemesis, Enigma, and Loki viruses are examples of this type of virus.

• Polymorphic Viruses:

Polymorphic viruses change their code so that the antivirus scanners do not detect them. Therefore, this virus produces varied but operational copies of itself. A polymorphic virus encrypts its code in different ways so that it appears differently in each infection.

The examples of polymorphic viruses are Involuntary, Phoenix, Stimulate, Evil, Virus 101, Proud, and Cascade.

Virus Symptoms:

If you notice the following changes occurring in your computer, then it may be possible that your system is infected by a virus:

-- When you are trying to open a program and it takes forever to load.

-- Your floppy disk or the hard disk is suddenly accessed and without any logical reason

-- You receive strange message saying, "Type Happy birthday Joshi" or "Driver Memory Error" appear on the screen.

-- The programs you are running may hang the computer or may not work at all.

-- You computer shows strange and unpredictable behavior like falling letters or a bouncing ball appearing on the screen.

If however, your data or files get corrupted don't give up, you can still recover all your corrupted or infected data. To recover these data you have contact data recovery companies, the technicians at these place can guide you through the recovery process. If you want to recover all the files then you can choose specific data recovery software according to your operating systems. However if you are concerned with certain specific file like word, excel, email then you can choose from various option offered by these recovery companies.

Stellar Information Systems Limited is an ISO 9001-2000 certified company specializing in data recovery and data protection software, services and solutions. Stellar offers a complete solution of data recovery software and lost data restoration programs for Windows (Windows 95, 98, ME, NT, 2000, 2003, XP), Apple Macintosh, Novell, Linux, Unix operating system and FAT, NTFS, NTFS5, HFS, HFS+, NWFS, JFS, EXT2 and EXT3 file systems.