I just bought CS:S and i got finished doin the update and i was ready to play but when i go to click launch game. it acts like its going to bring up the game (it brings up the lil box sayin preparing to luach...) then after that nothin happens. PLEASE HELP

I sorta had problem like this after an update. The image from the main CS:S menu would load but the menu wouldn't. Turns out hl2.exe was blocked by my firewall and the "allow/decline" option never popped up like it normally does. Hope it helps, if not you should head over to the Valve Support Site:
http://support.steampowered.com/cgi-bin/steampowered.cfg/php/enduser/std_alp.php

How would i go about unblockin hl2. from my firewall. i think im running norton anti virus?

explore your norton and you should fin a section where it says whats blocked and whats not.. scroll down to hl2 and all counterparts and make sure they are not checked.