I had the exact same problem as described by Moy. I was able to fix it further to LtSteve's (#30) post. I reinstalled my graphics card drivers and I was able to connect to steam and play my steam games. What had happened in my case was that I had mistakenly uninstalled my AMD software file. So, the next time I had to restart my computer (due to getting a blue screen) it was then that steam no longer worked. When I reinstalled my drivers (from ATI), AMD was also reinstalled at the same time. Thank you LtSteve!!!