Gmod Settings Saying that Games are Unavailable

Four games are unavailable in my Gmod Settings:
HL2: Ep.2
HL: Source
HL: Deathmatch
HL2: Loast Coast

Funny thing: I have these games! Why are they unavailable for Gmod use? What can I do?

Uh…they don’t actually add any content to the game. That is probably why.

Except Ep2. Try spawning ep2 stuff.

Actually, they all add things :
HL2DM add SLAM model.
Lost Coast add some models like the Fisher Man.
HL : Source add Half Life Source (Basically, Half Life 1) models.

Try running each of those games at least once.

Reinstall said games

hey can you guys check out my other question?
http://www.facepunch.com/showthread.php?t=940703