Now we know from DH, she even wrote a letter to the headmaster of Hogwarts, and when rejected and also after the death of her sister, she hated everything related to magic. But also she knew everything about magic too.

It did seem obvious in the first book that Petunia was jelous of her sister. Lily's parents were so proud. Maybe because of the the attention that Lily got, Petunia was neglected. Also we see in the Dealthy Hallows for certain that Petunia was jelous. She would call her sister names to make herself feel better about not having magical abilities.

I definitely agree that Petunia was jealous of Lily. There's no doubt about it. I don't see why else she would act so nasty toward Harry. It makes sense.

Petunia was obviously really jealous of Lily, who was pretty and smart and could do magic. I'm sure their parents loved both their daughters equally, but if they really did make more of a fuss about Lily, it's not so strange, that Petunia got the idea, that they preferred Lily, even if that wasn't fair to either Lily or their parents. And when she wasn't allowed to go to Hogwarts with Lily, she decided to hate magic and consider it "abnormal" and "freaky" instead. And when she met Vernon Dursley, he sure encouraged those feelings, which just made things worse.

It's just a shame, that Petunia had to move those hard feelings onto Harry, who after all was just an innocent child. Petunia is very similar to Snape and Filch, who also let their jealousy and bitterness turn them into nasty people, who loved tormenting innocent children, just because they could. (Okay, some students might have misbehaved or broken some rules, but they still didn't deserve the treatment, that Snape and Flich would give them). You might even feel a bit sorry for Petunia, Snape and Flich, but there's still no excuse for their behavior.

she was soooooooooo jealous of her sister, Lily.
that's shown in the memories in DH

It was also shown already in PS, when she complained about her parents only caring about Lily.

Petunia was definetly jealous of her little sister being able to go to Hogwarts. I think she changed her desire for magic to hate to make her jealousy easier to cope with.

Yup it's pretty obvious that she was jealous of Lily. Lily is clever and she got in the top magic school, which is brilliant. Lily got all of her parents' attention. On the other hand Petunia is just normal person. It is easy to see why she's jealous. No wonder why she hates Harry so much.

Well in my opinion just because she was jealous of Lily didn't mean she had to treat Harry the way she did. Harry couldn't have prevented his parents deaths and or prevented him living there untill his "manhood" in the wizarding world.
I never have liked her.
I'm pretty excited to see Snapes memory where it showed her being superly jealous of Lily. That will be epic!

Indeed, she had no right to treat Harry the way she did.

I think her hatred of magic came from a few things. Jealousy is definitely one of them, I mean who wouldn't be jealous if their little sister got to go to an awesome place like Hogwarts and be a witch and you didn't? It seemed to have impacted the sister's relationship a lot. Then Harry is living with the Dursleys and showing signs of magic all over the place as he grew up, it would be a big remider of what Petunia missed out on. Also, I think as much as she thought Lily was a "freak" she still loved her deep down and was very sad about her death, which only added to her being against magical things. It kind of ruined their relationship and then a wizard killed Lily, must be tough from Petunia's point of view if you really think about it.

My main problem with Petunia is rather than working her jealousy and fear out in a healthy way she took it out on her young nephew who needed to be loved and cared for not resented and abused. I mean it's totally unfair to Harry, because other than being a wizard and not getting killed by voldemort as a baby he didn't really do anything.

Absolutely, no matter how jealous Petunia was at Lily, she should never had neglected/abused her son like that. I can't understand how Dumbledore could decide, that she was the best candidate for being Harry's foster mother, even though he had his "reasons" to choose her. But we must also remember, that Petunia was married to Vernon Dursley, who did nothing but encourage her hatred against magic, and anything else, that wasn't "normal" and "acceptable" in their world. If she had married a better man, things might have turned out different as well.

O she was definatley jealous of her sister i would be lol in the seventh book it said she sent dumbledore a letter asking if she could come

She sent dumbledore a letter asking if she could go to hogwarts and he said no. Well it wasn't as point blank as that, but he was apparantly really nice in the letter back.

You got that right.

I thought he was very envious with lily, I think it was not Dumbledore once said if the petunias wrote to him that he was allowed to enter into Hogwarts as well

Yeah,it has been confirmed.

Yes she wrote him a letter. Aww sly she wanted to be a witch.

Of course she's jealous! Anyone would be though. In the seventh book (I think) JKR explains how Petunia sent Dumbledore a letter asking to join her sister but was turned down which I believe she held a strong grudge from that point on.