Hey guys,
i know that GPU mining is not good at this difficulty, but ATM i don't have to pay for the electricity so i decided to mine a little bit. I am on BTC Guild, and yesterday I was mining, with two of my GPU's. Radeon HD 7850 and Radeon HD 6870. But today any of my mining programs don't want to run or communicate with my GPU's. I was able to check that CG Miner is writing: "no devices detected either gpu"
Does someone can help me with it?

Thank you for all of you. Have a nice day