Correção: Advantages and disadvantages using the computer

[1][2] Using the computer, as everything in our lives, has advantages and disadvantages. Computers are the most well-known machines of the last hundred years. [3]

On the one hand, the biggest advantage of computers is [4] allowing people across the world to communicate through the use of email, social networks, chats, as well as blogs and forums too. Computers also allow people to look up information using search engines such as Google, Yahoo, Bing, and Whatnot [5], rather than use books [6]. However, when we look up information on the internet, we often don't know what to select, because of the large amount of information available online.

Moreover, computers allow us to make backup copies of the work easily, without having to rewrite everything [7]. [8] People can also work from home without having to spend much time with transportation; in turn, they can spend more time with their families.

On the other hand, the biggest disadvantages are: the possibility of being infected by viruses, having important information stolen - such as bank account information, addresses, personal information and so on. Besides, computers can be quite costly and become obsolete very quickly; every single month, computer companies launch new models, and if we want to keep pace with the speed of the innovation, we will have to pay for it.

Using computers can also bring us some health problems, such as eyesight loss and backaches, due to bad posture. In a nutshell, we have to use computer with moderation [10].

Correction key:
Italic: not necessarily wrong, but it probably did not sound good the way it was originally written.
Bold: problems with grammar, vocabulary or spelling.

Recommendations:
[1] Shouldn't your text have a title? When in doubt, provide one.

[2] I changed the order of your sentence; it looks better this way, don't you think?

[3] Your first paragraph is too short and it lacks the basic features when it comes to academic writing: it must introduce the matter, subject or issue you're going to address and it has to present your main thesis, which is going to be explored in the following lines.

[4] Problems with concordance here; if the noun is in the plural, so should be the verb and vice versa.

[5] Once you're citing nominally search engines here, their names should all be capitalized: Google, Yahoo, etc. The rule is quite similar to that of the Portuguese language.

[6] Since you're talking about books in general, you should not use the definite article the here.

[7] When you say: "(...) without having to re-write everything again", you're being redundant (rewrite = write again). Also, the correct spelling would be rewrite.

[8] The expression "what´s more" is quite informal. When you're writing academic texts, prefer the usage of connectives like furthermore, moreover, besides and in addition, which convey the same idea in a proper manner.

[9] I have never seen anyone claiming to have lost one or both of their eyes due to computer usage. I suppose you meant losing eyesight.

[10] A last piece of advice: read! The only way to write properly is by reading content from different sources, such as magazines, newspapers, online blogs, books, etc. Find out what amuses you the most and start reading for ten minutes a day; the results will amaze you.

Cheers!