Computers and school

How could a normal person consider that I shouldn't receive credit on an assignment just because on the teacher's computer the website doesn't work like on the computer I created it? I mean... it's retarded. I told her to come and see that on the computer (at school) I made the website, it works but she said it doesn't matter, and that she believes me but she wouldn't give me the damn credit! I don't care why it doesn't work on her computer but I used the manage website option in Dreamweaver as she told us!!! If she does that one more time I'm gonna go talk to the counselor. Grrr... I hate school so much...