My best gift is computer. = The best gift I have ever received was a computer. 
I was gruate high school, my father gives me the computer. = My father gave me a computer on my high school graduation. / It was my graduation gift from my father.
My family were had computer but that is very slowly. Sometimes it makes me mad. = My family already had a computer at that time but it was very slow and  sometimes made me mad when  I was using it.
He said "Do study more and do little paly the game" and gave it. = My father said, "study more and play a little".  But i can't = I couldn't  do it. It is = It was defficult for me. I palyed game a lot and do study little. = I ended up doing the oppossite. I played more and studied less. 

But it hasn't just disadventage. It has good thing. = But, it wasn't all bad for me. It had its advantages. 
I can well deal with computer( hard ware and soft ware). = Because of it, I can use the computer well. 
Nowday my family ask me something problem or when they buy computer. = Nowadays, when my family is having a computer problem, they always ask me to help them.