Corrupt File

When I try to install CF it tells me that the file that was being installed at the time is corrupt and it asks me if I want to retry, skip that file, or abort. Retrying doesn't work, as it just tells me to retry again or abort. I don't that skipping the file is a good idea either, and aborting...well it aborts. I've had the game installed before and it worked great. Any ideas? I'm running AVG anti-virus, and W7 is my operating system, but like said, it's worked fine before.