I've got a w810i, and so has my sister. When I connected to her cellphone, I started to get her phonebook and get all her sms.

I got her phonebook and sms, and then I closed the program.

When I connected afterwards, I decided to try some of the other functions. So I tried the "Turn off phone" function. It worked, her phone got turned off. But whenever she tries to turn it on again, it just switches from black to white from black to white and so on. It never got to the pin-code screen. And it ain't possible to turn it off. So to stop it, she has too remove the battery. Now I don't know what to do

If I can't fix it, I have to pay 400$ to my parents, so they can buy her a new one.

Help would be highly appreciated