Your going to have to be a lot more specific that is a very broad answer.
there is basic diff b/w computers in accords of digonal size,memory,processor speed etc.
There are quite a few differences between a compact computer and other computers. Compact computers are easier to take with you.
Every brand of computer uses different manufacturers, which translates into differences between the technologies being used to make the computers, differences in the raw materials being used, and differences in the choices made for the computers, such as what types of components to use at all. Because of all these differences, each computer company has real differences between its' products and those of other companies.
NOTHING!
computers weren't invented in 1856.
There are many differences between having a laptop and desktop. Laptop computers really a great where you are moving around the house desktop computers won't allow you to move around.
Fundamentally there is no difference between an HP computer and an IBM compatible computer. They both use the same type of technology and software. The differences will be in how much memory, hard disk space they have, the prices, and the warranties.
Desktop computers differ from laptops and notebooks because they are not portable like laptops and notebooks. Desktop computers are usually your personal pc computers with windows and/or apple operating systems. Laptop computers are great as they are portable and can be used anywhere there is wifi service as are notebooks.
4th generation of computers are acts as user define computers but 5th generation computers are act as automatic computers by means it doing its works automatically
Early Computers were large in size while today computers are compacted .Early Computers were Vaccum tube and transistor based while today computers are ICs based.Early Computers were slow and today computers are fast.Early Computers were used punch card for storage while today computers used Secondry storage ( Hard Disk) for storage.Early Computers were not user friendly todays computers are user friendly
Genetic differences
IT is using knowledge of computers to perform tasks such as word processing whereas computing is to do with programming languages such as basic, visual basic or C++
Apple World deals specifically with one brand of computers - PC World covers any IBM compatible PC