My dialog about computers.

-Hi, I haven’t seen you for a long time!
-Oh, hi! How are you?
-Fine, thanks, and you?
-I’m fine, too.
-Could you tell me something about modern computers with GUI (graphical user interface). I have a computer with an operating system called MS DOS. And I want to buy a new computer.
-Oh, it’s too old. Ok, I’ll tell you something. What would you like to know?
-Firstly, I want to know what can I do with it?
-You can type texts, draw objects and diagrams. While you are drawing you can shape, move, transform, copy and fill the objects/ When you are typing texts you can format, edit and copy them. Both texts and drawings can be deleted and saved, and if you had a printer you could print the information displayed on the screen. Also, you can play different games.
-And how can I communicate with the help of the computer?
-The Computer gives us access to the Internet, where you can get all kinds of information, correspond with your friends and debate urgent problems on-line.
-But, does the computer give us any harm?
-Yes, of course. If you sat at the computer for a long time you might get problems with your eyes and posture. Also a lot of people, mostly pupils, have such illness as gambling.
-I see that computer is very useful nowadays, though it gives us some harm. Thank you. I will look for a good computer/
-I wish you success. If you need some help ask me. Good bye.
-Bye.

I try to correct you but I'm not a native english speaker. I hope help you or at least some native speaker see it and correct it.

Pay attention to the articles and the conditional. BTW a think your have a great level of English.