Black screen after flash ?

A

AC Question

I have a Asus Memo Pad HD 7 from a friend which was full of malware and other ****.
Now I wish to rooting it again but there is apparently something went wrong and now the screen is completely black and I can start him even more.
Contacted Asus and say send because they have special software to fix this.
Does anyone know how to fix this by myself ?
When i tried connect whit the pc i get a error 44, and windows does not recognized the tablet.