I will probably forget a few things, but its been a long day and even longer night(im feeling mighty staby at the moment). Anyway few things to try/do
try running it in compatibility mode, (95 or 98 preferably), often with old software like that it will get around your issue, and you can try restoring your settings to where they were. Check the integrity of your game files, steam apps have the built in functionality for that(just go to your library of steam games(while in steam, not on the actual disk), open properties, and click the check integrity button).
Any time you have power problems it can cause hardware damage as well. so when you open the game and the screen goes black does it stay this way after you close the game?(in other words you have to reboot to get your screen back) if so then your PSU got damaged and needs to be replaced. Have you re-seated your graphics card? sounds crazy but yeah sometimes it works.
Other than that if you have already redone your video drivers the most probable problem is that it created an out and out conflict with the card. to fix that you can A re-install windows(im assuming thats your OS) or B uninstall/re-install all your games(keeping save files is fine) but you need to completely remove counter stirke, half life, and even steam would be a good idea, and since your going that far might as well make a clean sweep and get windows media player and any other playback programs as well. THEN re-install your video drivers, and re install all programs. Its a PAIN IN THE ASS when this happens, but it does occasionally happen to where some crazy conflict appears, but doesnt show against any one program/utility. I had it happen once to my CD-ROM drive. no new programs installed in 6 months and it just quit working. finally the only thing i hadn't done was the above. so i got rid of anything that used the CD-ROM drive, redid its drivers and re-installed everything and everything worked perfectly.
The card itself could have been damaged. Test with known good hardware, or with your on board video card if you have one(removing the card itself for that test obviously).