Finally ...

[Blackthorn27]

... got CivIV back after uninstalling it because of various computer problems relating to BSOD's (which I think I've tracked down to a poorly secured/housed videocard). Phew, but it was hard work though - took hours. Kept getting CRC errors when I tried to install the program from the DVD ROM (I'm a UK user). That made me think the DVD was damaged (because the error message suggests that: 'The medium from which you are running the setup [i.e. the DVD] maybe corrupted ...'. Kept chipping away, though, and after a few registry tweaks (i.e. deleting all previous CivIV and most CivIII entries from the registry) eventually the game loaded up fully from the DVD. Once that was done had to uninstall the program again to get it to clean out the registry properly. Then got more CRC errors when I installed the latest patch download. (That made me think that it couldn't have been the DVD that was causing them - had to be something bad in the registry, or something). Kept chipping away and eventually the patch loaded fully so that I could uninstall again for a clean registry deletion. Since that was done the program is FINALLY running properly and is stable.

Does anyone know what causes CRC errors? They are weird things, aren't they - because first there was a whole bunch of 'um then they gradually got fewer and now there are none - strange. Must have something to do with me buggering about with the registry between me uninstalling the program (many moons ago) and me now trying to re-install the program, right?

Anyway, just glad I've got CivIV back on my computer. Was touch and go there for a while.

Now to get down to some serious gaming again.

 

[auldian]

Frequently it's media if it occurs during a software installation. Hardware and cables can also cause them.
There is a "short and sweet" discussion here.