From that PC that is having the problems are you able to navigate to any of the mirrors listed?
For example http://mirrors.fedoraproject.org/mirrorlist?repo=fedora-$releasever&arch=$basearch seen as this is the only one enabled above.
If not, it could be DNS. So are you able to ping domain names?
You don't mention if this is 32bit or 64bit but here is a 32bit repo