My advice for issues like that is usually to reinstall Half-Life. Sorry I can't get any better technical advice then that.
I still play CS. Here in Simi a bunch of people from our school last year play, we have a clan and server. Playing in multiple leagues at the moment (Cal-O and some OGL one) which is extremely fun, perhaps the most fun I've had with CS. Having defined strategies for each map, instead of playing more Deathmatch style in public games, is a unique and fun experience.