Sounds to me like you simply need to uninstall and reinstall. The only computer that FH has difficulty with is Mac because there is no mac version unless you have some sorta program for that, and the visual problem on your XP could be possibly solved by changing the rendering subsystem.
*Edit
There are also some bugs going on with the server right now, and a patch that needs to be installed before it will allow you to go online. Make sure you install the patch.