Radiation Alert: Episode 1 file

Installation:
I used the old installation path first: C:\Program Files\Steam\SteamApps\account\half-life\ but it doesn't work, now you must do the following.
After the Half-life update on Steam unzip the file radalert into the following directory:

C:\Program Files\Steam\SteamApps\common\Half-Life\

The game should appear in the library.

If the game is lagging try software mode.
Change between opengl and software mode:
I can change between each tab in the options(if software mode is activated) when i click below the buttons, or at the lower border.