Steam games crash while loading

[deathsquire36]

So far Steam has been useless as far as solving my problem, so I'm looking everywhere I can for help.

I recently bought Team Fortress 2 through Steam. I had Steam collecting dust on my system for awhile, since it had been awhile since I've played Half Life 2 or CS:S, both of which used to work perfectly fine when I had initially installed them. Reactivating Steam after all this time, it has updated itself, and I have downloaded Team Fortress 2. After this, none of the three games work anymore. I've tried uninstalling Steam and reinstalling it. I've uninstalled TF2 and reinstalled it. My system requirements are definitely fine to run the game. Here's my problem:

All three games in Steam show 100% - Ready, yet, when I click launch, the launching bar comes up, stays there for about 10 seconds, then gives me this error:
Unable to load "c:\games\valve\steam\steamapps\deathsquire36\team fortress 2\bin\filesystem_steam.dll"
I've tried using Steam to test the game's file integrity, and it always comes up clean. I've deleted all the bin folder files and let Steam redownload them again and again, but it never helps. I still get the same error. Please help!!

These are my system requirements:
Pentium M 2.13 GHz
nVidia GeForce Go 6800 - 163.75 drivers
1 GB RAM
Directx9.0c

I used to be able to play Half Life 2 and CS:S without ANY problems, so I know my system requirements are fine. Some Steam update will not allow me to play ANY of my games anymore. Effectively, I paid $30 for Team Fortress 2, and ended up losing $80 worth of games. What can I do to fix this?

Your help is GREATLY appreciated!!

Patrick

 

[Rapstah]

Try reupdating Steam. Remove all files except for Steam.exe and the SteamApps folder, run Steam.exe, let it update, try again, and then report back here.

 

[deathsquire36]

I deleted everything in the Steam folder, including all the other folders (except SteamApps), and I deleted everything inside the SteamApps folder besides the GCF content files of course. Steam updated, reinstalled all the missing files. I tried launching TF2 through Steam, got the same message:

"Unable to load C:\Program Files\Steam\SteamApps\deathsquire36\team fortress 2\bin\filesystem_steam.dll"

Keep coming with suggestions guys! Your help won't go unnoticed. I've lost many hairs on my head after pulling them out over this issue.

Pat