What am I doing wrong? Daughter and computer?

I am constantly getting really angry with my daughter because of her computer usage. I keep on trying to be fair with her, but she's taking the piss. Like yesterday, I realised that she'd been on her computer for nearly 6 hours (Id been out at work), and when I asked her if she'd written any of her book report that is due in 2 weeks, or practiced her violin for her grade 5 exam, or written a thank you note to some friends etc etc, she just started crying, said that she was an idiot and promised it wouldn't happen again. Then this morning I was trying to get her up, and when I went in her room she was on her iPhone playing games, and to be honest I just lost it.

I don't understand how she can go from crying and sincerely being upset at her own lack of achievement, swear that it wont happen again, and then do it the very next day. I just don't get it.

What am I doing wrong?

Read more: What am I doing wrong? Daughter and computer?