I just bought The Orange Box (hooray to Black Friday!) and everything installed fine. When I try to play HL2, it crashes at the first in-game loading screen after you talk to Barney and jump out the window. I get an "engine error" and it brings me back to the desktop.

Here's my computer specs:
WinXP Pro SP2
Asus P4P800SE
P4 3.0 ghz Prescott
ATI Radeon X1600 with 7.10 driver (I couldn't get 7.11 to install)
1gb Crucial RAM
~30gb free space

I tried running CS Source and it worked fine. I've tried cleaning the DirectX drivers and reinstalling them to 9.0c and that didn't solve the problem. I also tried looking for the 4 autosave files and changing them to read only but I don't seem to have them. Please help! Thanks