Forum:Problem with loading the Expansions

Hey, in need of urgent help here.

I was stuck while playing the Mothership Zeta-expansion. There was a glitch in the room overlooking earth, where a alien hologram was supposed to appear, but it didn't. So I then looked here on the net for possible ways to solve it. I then read someone writing that I should clear the cache of the system. So I did.

After this 'clearing', all that had with the Expansions to do, was gone. Not only Mothership, all other additional Expansions-quests are gone. Which really pissed me off.

So, do I have to restart the game completely from the beginning? Or how do I get the expansion loaded back?

I have already put Disc 2 in to reload all expansions, it still doesn't come back when I play..anybody knows what to do?