Well I played HL2 for a couple of hours last night, all fine and dandy. About a half hour after quitting, Steam gives me a message "The cdkey you've registered has already been to an existing steam account, and is therefore invalid..". Uhhh, yeah.. ok. I'm praying that this is just a error and it gets fixed ASAP, but now I can't even play HL2 or CS. And before you ask any questions, yes, the first time I registered the cd-key, it worked, and yes I registered it to the same account. Also, I purchased the hard copy of the game. This issue has probably already been addressed, but I have to be at work in a couple minutes, so I couldn't have enough time to search for it 😛