I've met a random guy online on Borderlands. At the start of the game he threw away a couple of orange Roze Omega shields ( that aren't in the categorie of shields in the menu) and the they had a Power over 470000000 and he also gave a machine gun away that had no lvl requirements, could shoot 3 bullets at a same time, was white colord in rarity and had the power of over 21000 and it would kill EVERYTHing with 1 shot.
Could you tell me where I can find such powerful objects?

Sounds like hacked items to me and best avoided, unless you want to lose your account.

It was on my PS3 so it's almost impossible to hack it. Maybe there is a supersecret room...