Laptop computers are small portable computers, which you can easily operate keeping on your lap. At the present time, laptop computers come with all the features offered by a standard desktop PC such as keyboard, display, a pointing device as well as speakers. A laptop computer is powered by a rechargeable battery, which can work up to a few hours.

- Desktop Replacement:

Desktop replacement laptop computers are planned as a substitute to desktop PCs. They offer up all the basic features of a desktop PC and are usually bigger and heavier. They come with a huge display screen, but a shorter battery life. Dell XPS M140 Laptop belongs to this category.

- Subnotebook/Ultraportable

If you are someone who is always on the move then ultraportable laptop computers are the best option for you. As compared with other laptop computers, they are smaller, lightweight and have a longer battery life. They have smaller display screen and lesser hardware features like least number of ports. Sony VAIO C1 is an example of Subnotebook/Ultraportable computers.

- Netbook

Netbook laptop computers specialize in wireless communication and web access. They are lower in weight and power-efficient. If you are searching a laptop computer with higher internet accessibility traits then the netbook is the best choice for you. Asus Eee PC belongs to this group.

- Rugged Laptop

If you in search of something, which could survive harsh environments such as dust and water then buy a rugged laptop computer. They are insensitive to harsh usage conditions like strong vibrations and intense temperatures. As compared with other laptop computers they are heavier and pricier. Panasonic Toughbook is an example of a rugged laptop computer.

- Tablet PC

Tablet PC's are laptop computers with a touch-screen interface, which may or may not have a keyboard and are controlled with the help of a stylus or digital pen. They are costly, but are easy to use, particularly for those who are not used to using a keyboard and mouse. HP Compaq tablet PC comes under this category.

Computer security is a big worry now-a-days. It is concerned with control of risks linked to computer usage. It is a process of prevention and detection of the unauthorized use of your personal computer. It means keeping your PC as well as your information in a safe mode. Computer security is the ability of a system to defend data and system resources with regard to privacy and integrity.

There are a variety of computer programs like Virus, Trojan, Adware and Spyware, which can break the computer’s security system. Virus is a program, which normally spreads through e-mail attachments, web pages, and file sharing, floppy and zips disks. Virus propagates itself by traveling from file to file and from computer to computer, often annihilating file in the process.

Trojan can harm the PC by leaving the infected computer open for hackers to gain access, install software and use the computer for illicit purpose. Adware and Spyware programs automatically enter your PC via freeware programs. They gather information from your PC and report it back to the company, and to exhibit popup windows of advertisements whether or not you are viewing internet sites at the time.

One of the most effectual methods to stop Spyware and Adware is the use of computer firewall protection. These programs get rid of incoming Spyware and Adware, which are attached to the legitimate information that you download when browsing the web. You can install anti-virus software to defend your PC from virus’s attack.

Anti-virus software scans the files on your PC. Besides, these software items can secure your PC as well as data by using passwords. When you make passwords, don’t make them simple. Don’t use your name, your birth date or your social security number.

A laptop is a small mobile personal computer, which normally weighs from 1 to 3 kilograms. It has a benefit over the desktop PCs as it can easily be transported from one place to the other because of its portability.

There are hoards of laptop models available in the market with different features. Some high quality laptop computers have several connectivity options like wireless network cards and centrino technology etc.

Laptop technology is moving ahead at a fast speed. In reality, there is a whole new generation of notebook technology every two years or less. Laptop computers are usually classified as per their weights as Notebooks, Standards, Extra Large and Ultralights laptops. They run on battery, you can use them for 3-5 hours at a stretch. Some of the models need at least 256MB RAM to run the operating systems.

Your selection of laptop computer will circle around your personal requirements but when selecting, you should give weightage to the factors such as the screen, speed, weight, memory, battery backup and cost.

Earlier, laptops were thought suitable generally for "specialized field applications" including the military, the Internal Revenue Service, chartered accountants and salespeople. But today, there are already more laptop computers in usage as compared to desktop PCs in businesses and laptop computers are becoming obligatory for pupil use and more popular for general use.

In the year 2008, more laptop computers as compared to desktops were sold in United States and it has been projected that the same landmark will be achieved across the world this year.

You can also shop on the internet and also purchase cheaper refurbished laptop computers. You can also take laptop computer on rent. Most of the enterprises are choosing this option as it is totally flexible, needs no capital budget and can be accomplished with a company credit card.