What is stumbling block in my study?

　The most interrupted factors in my studying are messenger and
　
sleeping. These days, the assignment want something to do by
　
computer, so when I turn on the computer, I always do a
　
messenger, which is Nate-On. In the messenger, I send a message
　
and have a conversation with my friends, eventually I spend much
　
time on talking with them. Though I stop it to do assignment, I'm
　
so tired from do computer. So I do not assignment although turn
　
on computer. After that, I always regret to it. Now I have to
　
reduce the time using Nate-on, so I will delete Nate-on file from
　
computer. It sounds like ignorance to solve the problem, but I
　
think this is the best way.