Disadvantages of Laptops...

1.Performance






While the performance of mainstream desktops and laptops is comparable, laptops are significantly more expensive than desktop PCs at the same or even lower performance level.The upper limits of performance of laptops are a little bit lower, and "bleeding-edge" features usually appear first in desktops and only then, as the underlying technology matures, are adapted to laptops.
However, for Internet browsing and typical office applications, where the computer spends the majority of its time waiting for the next user input, even netbook-class laptops are generally fast enough. Most higher-end laptops are sufficiently powerful for high-resolution movie playback, 3D gaming and video editing and encoding. However, laptops are disadvantaged when dealing with database, math, engineering, financial software, etc.
Some manufacturers work around this performance problem by using desktop CPUs for laptops.





2.Upgradeability






Upgradeability of laptops is very limited compared to desktops, which are thoroughly standardized. In general, hard drives and memory can be upgraded easily. Optical drives and internal expansion cards may be upgraded if they follow an industry standard, but all other internal components, including the CPU, motherboard and graphics, are not intended to be upgradeable.
The reasons for limited upgradeability are both technical and economic. There is no industry-wide standard form factor for laptops; each major laptop manufacturer pursues its own proprietary design and construction, with the result that laptops are difficult to upgrade and have high repair costs. With few exceptions, laptop components can rarely be swapped between laptops of competing manufacturers, or even between laptops from the different product-lines of the same manufacturer.
Some upgrades can be performed by adding external devices, either USB or in expansion card format such a PC Card: sound cards, network adapters, hard and optical drives, and numerous other peripherals are available, but these upgrades usually impair the laptop's portability, because they add cables and boxes to the setup and often have to be disconnected and reconnected when the laptop is moved.








3.Ergonomics and health








Because of their small and flat keyboard and trackpad pointing devices, prolonged use of laptops can cause repetitive strain injury.Usage of separate, external ergonomic keyboards and pointing devices is recommended to prevent injury when working for long periods of time; they can be connected to a laptop easily by USB or via a docking station. Some health standards require ergonomic keyboards at workplaces.
The integrated screen often causes users to hunch over for a better view, which can cause neck or spinal injuries. A larger and higher-quality external screen can be connected to almost any laptop to alleviate that and to provide additional "screen estate" for more productive work.
A study by State University of New York researchers found that heat generated from laptops can raise the temperature of the scrotum when balancing the computer on one's lap, potentially putting sperm count at risk. The study, which included roughly two dozen men aged 21 to 35, found that the sitting position required to balance a laptop can raise scrotum temperature by as much as 2.1 °C (3.78 °F). Heat from the laptop itself can raise the temperature by another 0.7 °C (1.26 °F), bringing the potential total increase to 2.8 °C (5.04 °F). However, further research is needed to determine whether this directly affects sterility in men.



A common practical solution to this problem is to place the laptop on a table or desk. Another solution is to obtain a cooling unit for the laptop, these units are usually USB powered consist of a hard thin plastic case housing 1, 2 or 3 cooling fans (the whole thing is designed to sit under a laptop) which results in the laptop remaining cool to the touch, and greatly reduces laptop heat buildup. There are several companies which make these coolers.
Heat from using a laptop on the lap can also cause skin discoloration on the thighs.








4.Durability





Due to their portability, laptops are subject to more wear and physical damage than desktops. Components such as screen hinges, latches, power jacks and power cords deteriorate gradually due to ordinary use. A liquid spill onto the keyboard, a rather minor mishap with a desktop system, can damage the internals of a laptop and result in a costly repair. One study found that a laptop is 3 times more likely to break during the first year of use than a desktop.
Original external components are expensive (a replacement AC adapter, for example, could cost $75); other parts are inexpensive—a power jack can cost a few dollars—but their replacement may require extensive disassembly and reassembly of the laptop by a technician. Other inexpensive but fragile parts often cannot be purchased separate from larger more expensive components. The repair costs of a failed motherboard or LCD panel may exceed the value of a used laptop.
Laptops rely on extremely compact cooling systems involving a fan and heat sink that can fail due to eventual clogging by accumulated airborne dust and debris. Most laptops do not have any sort of removable dust collection filter over the air intake for these cooling systems, resulting in a system that gradually runs hotter and louder as the years pass. Eventually the laptop starts to overheat even at idle load levels. This dust is usually stuck inside where casual cleaning and vacuuming cannot remove it. Instead, a complete disassembly is needed to clean the laptop.
Battery life of laptops is limited; the capacity drops with time, necessitating an eventual replacement after a few years. The battery is often easily replaceable, and one may replace it on purpose with a higher end model to achieve better battery life.








5.Security








Being valuable, common and portable, laptops are prized targets for theft. The cost of the stolen business or personal data and of the resulting problems (identity theft, credit card fraud, breach of privacy laws) can be many times the value of the stolen laptop itself. Therefore, both physical protection of laptops and the safeguarding of data contained on them are of the highest importance.

• Most laptops have a Kensington security slot which is used to tether the computer to a desk or other immovable object with a security cable and lock.


• Modern operating systems and third-party software offer disk encryption functionality that renders the data on the laptop's hard drive unreadable without a key or a passphrase.


• Some laptops also now have additional security elements added by the consumer, including eye recognition software and fingerprint scanning components.