A personal computer is a general-purpose computer whose size, capabilities and original sale price make it useful for individuals, and is intended to be operated directly by an end-user with no intervening computer time-sharing models that allowed larger, more expensive minicomputer and mainframe systems to be used by many people, usually at the same time.
Software applications for most personal computers include, but are not limited to, word processing, spreadsheets, databases, web browsers and e-mail clients, digital media playback, games and many personal productivity and special-purpose software applications. Modern personal computers often have connections to the Internet, allowing access to the World Wide Web and a wide range of other resources. Personal computers may be connected to a local area network (LAN), either by a cable or a wireless connection. A personal computer may be a laptop computer or a desktop computer running an operating system such as Windows, Linux (and the various operating systems based on it), or Macintosh OS.
Early computer owners usually had to write their own programs to do anything useful with the machines, which even did not include an operating system. The very earliest microcomputers, equipped with a front panel, required hand-loading of a bootstrap program to load programs from external storage (paper tape, cassettes, or eventually diskettes). Before very long, automatic booting from permanent read-only memory became universal. Today's users have access to a wide range of commercial software, freeware and free and open-source software, which are provided in ready-to-run or ready-to-compile form. Software for personal computers, such as applications and video games, are typically developed and distributed independently from the hardware or OS manufacturers, whereas software for many mobile phones and other portable systems is approved and distributed through a centralized online store.12
Since the early 1990s, Microsoft operating systems and Intel hardware have dominated much of the personal computer market, first with MS-DOS and then with Windows. Popular alternatives to Microsoft's Windows operating systems include Apple's OS X and free open-source Unix-like operating systems such as Linux and BSD. AMD provides the major alternative to Intel's processors.
What' s definition of laptop? (Wikipedia)
A laptop, often called a notebook, is a portable personal computer with a clamshell form factor, suitable for mobile use. Although originally there was a distinction between laptops and notebooks, the former being bigger and heavier than the latter, in modern usage there is often no longer any difference. Laptops are commonly used in a variety of settings, such as at work, in education, and for personal multimedia.
A laptop combines the components and inputs of a desktop computer, including the display, speakers, a keyboard, and pointing devices (such as a touchpad or trackpad) into a single unit. Most modern-day laptops also have integrated webcams and built-in microphones. The device can be powered either from a rechargeable battery or by mains electricity from an AC adapter. Laptops are diverse devices and specialised kinds, such as rugged notebook or convertible computers, have been optimized for specific uses. The hardware specifications significantly vary between different types, makes, and models.
Portable computers, which later developed into modern laptops, were originally considered to be a small niche market, mostly for specialized field applications, such as in the military, for accountancy, or for sales representatives. As portable computers became closer to the modern laptop, they became widely used for a variety of purposes.
Sick computer - what can you do?
You should keep your computer safe. What do You really know about viruses? If You think they are not dangerous, you are in a big mistake. In fact, computer virus can destroy all your data, but damage could be worse. What can you do when your computer gets infected? First try to use an antivirus program to scan your disk, it is still possible to remove a problem. What if it will not work?
In the worst case, call for help to a computer service - they will know what to do to fix your computer and save your files.