i think she knows quite alot cause of her sister

I agree. I think she is a witch. She may have just been scared to show her true identity!!! Maybe she decided just to stay low, and get rid of her powers...And she knows the whole story of Voldemort, and she knows that Harry's in danger...

i guess she may know of voldemort.....bu-ut shez definitely not a witch....

Uncle Vermon even knows about Voldemort.

ok....dey both know about him but i guess dey dont completely understand the seriousness of d situation or d danger harry is in.....