Failed:Bad Login

Put the summary of the bug you're having here
I have recently tried to login to several servers without luck what so ever. It continues to give me the error upon clicking Join Server "Failed: Bad Login." I think I have a Premium account. I was also wondering if you could help me with changing my account, I won it in a contest and have no access to the account through minecraft.net.If you can, please help me.

Steps to Reproduce:
1. Log into my account
2. Join mc.Pyrostasis.com = Failed Bad Login
3.