I had a problem with that too. i ended up spending about 3 MONTHS with a customer support dude, trying to figure out what was wrong! ok, the things i had to do were.....
1. Uninstall CS: condition zero
2. Create an account with steam
3. register my game
4. Install the game again
5. update. (which froze sometimes)
6. when it froze, delete the registry files in counter strike.
hope it works for u dude!