While you are shopping around, it’s important to keep in mind some of the benefits that go along with owning different types of computers.  To that end, this article provides five important reasons to purchase desktop computers.

- Desktop computers are typically much more affordable than notebook computers.  With notebooks, you are paying more for the convenience of portability.  For as little as $299.00, desktop computers can be purchased from one of the leading manufacturers and a notebook computer for as little as $499.00.
- Unlike notebook computers, replacing a keyboard, mouse, speakers or even a monitor does not require having your computer serviced by a professional repair shop.  Because notebook computers have everything built in, including the aforementioned features, it is more difficult to replace a keyboard or monitor as opposed to desktop computers, which operate on external connections.

- In the event of an unlawful entry into your home, desktop computers are not as likely to be stolen because of their weight and bulk.  Notebook computers, on the other hand, are small and portable.  This, alone, makes them more appealing to a thief than desktop computers.

- Desktop computers are stationary by nature.  Unlike a notebook computer, which can easily be moved from room to room, they are less likely to be dropped or broken because they are not moved as often.

- The vents on desktop computers are located on the back of the tower, which allows for proper ventilation that will help to prevent the computer from overheating.  Notebook computers, on the other hand, feature only one vent on the back with the remaining underneath the base.  If placed on a table, the air vents can become blocked and the computer may overheat.  If prolonged use leads to overheating, damage may result.

When choosing from the many desktop computers on the market, always make sure that you purchase from a manufacturer who has experience in creating computers.  Even though they are more affordable than notebooks, desktop computers are not cheap.  With an investment that involves several hundred dollars, you will want to consider the length of time the manufacturer has been in business, their reputation with customers and their warranty.

Additionally, when choosing any system, including desktop computers, always look at the potential for future upgrading.  As you grow, you will want your computer to grow with you and a part of that will include a slight upgrade from time to time.  This is the only way to get the best use of your desktop computers and make sure that your investment is one that lasts for years to come.

If the virus is found in any of the PC’s that PC should immediately be isolated. The virus can be removed by giving an antidote by studying the virus. The machine should be put into use only after the virus is eliminated.
Viruses and such

A Virus is defined as a program inserted into another program. It gets activated by its host program. It replicates itself and spreads to others through floppy transfer. A virus infects data or program every time the user runs the infected program and the virus takes advantages and replicates itself.

There are two types of computer viruses ‘parasitic’ and ‘boot’ virus.

A Parasitic virus attaches itself to other programs and is activated when the host program is executed. It tries to get attached to more programs so that chances of getting activated is more. It spreads to other computers when the affected programs are copied. ‘Jerusalem’ and ‘Datacrime’ are parasitic viruses.

A Boot virus is designed to enter the boot sector of a floppy disc. It works by replacing the first sector on the disc with part of itself. It hides the rest of itself elsewhere on the disc, with a copy of the first sector. The virus is loaded by the computers built-in start-up program when the machine is switched on. The virus loads, installs itself, hides the rest of itself and then loads the original program. On a hard disc, virus can occupy DOS boot sector or master boot sector.
Some Reported Viruses

C-Brain: Amjad and Basit, two pakistani brothers, developed this software in January 1986 to discourage people from buying illegal software at throwaway prices. This was the most famous virus ever found and has a record of damaging few millions of personal computers. This is designed to stay in the boot sector of the disc or near zero sector. The virus enters the machine memory once the PC is booted with the infected floppy.

Macmag: This virus attacked Apple Macintosh computers only. Not much damage is reported because of this virus. This was not noticed on any IBM compatible PCs. It displayed a message of peace on the monitor and killed itself.

Cascade: This virus attacked IBM PCs and compatibles. The letters on the screen could be seen dropping vertically down to the bottom of screen after the virus picked them off in alphabetical order. This is a sort of parasitic virus. It attaches itself to other programs and gets activated when the host program is executed. It gets copied to other PCs when the programs are copied.

Jerusalem: Found in 1987 at Hebrew University, Jerusalem, this virus was designed to activate only on Friday, January 13 and delete all the files executed on that day. This infects the COM and EXE files. This is similar to Cascade virus in that it is parasitic in nature. This virus attaches itself to COM and EXE files to damage the data.

Daracrime/Columbus or October the 13th virus: This virus is similar to Jerusalem and was programmed to attack on October 13, 1989. Track zero of computer hard disk is destroyed and the contents of discs are rendered unreadable. This virus enters COM and EXE files and damages the hard disk. An antidote called ‘Vchecker’ was developed by the American Computer Society. Fortunately the virus was located in March 1989 itself and the damage reported after October 13 was minimal.

Bomb: This is also know as ‘Logic Bomb’ and ‘Time Bomb’. An event triggered routine in a program that causes a program to crash is defined as a ‘bomb’. Generally, ‘bomb’ is a software inserted in a program by a person working in the company.