I've been having a weird problem too, I doubt it's related though.
Whenever it loads up and gets to the point of displaying the 3d engine after joining the server, the window minimizes and I can't bring the display back up. I've been able to replicate the same problem by just launching CS:S, clicking on "Options," and selecting OK. I have no idea why this is happening.
If I run in windowed mode, this problem doesn't occur. Weird.