hldj.org

I installed HLDJ, then added Modular Combat to the game's list. Modular Combat is a Half Life 2 mod, so that might be the problem. Anyway, I try to start up Modular Combat with HLDJ, but it doesn't start up. I clicked the play button, and now HLDJ is STILL trying to start Modular Combat. Is there a problem or something? If it helps, here's the directory that I put in to add Modular Combat: C:\Program Files\Valve\Steam\SteamApps\SourceMods\modularcombat

Please help!

I'm not sure what you mean by "trying to start". Either HLDJ will launch the game or it will fail and tell you so. If HLDJ becomes unresponsive, post a screenshot and description of the moments leading up to and following it.
Otherwise if it is Steam that is hanging, then this is likely a problem with Steam. It could be a network problem, or one-time error. Try launching other games or Source mods and see what happens.

Oh, never mind. I fixed it.