I wouldn't go near any of this Windows 8 leak builds, firstly cause you have no idea if this build is genuine and also it’s been out for more than long enough now for malware writers to have injected code into it before releasing it to torrent sites and secondly they are nothing like the preview Microsoft gave us of Windows 8, there basically unstable dodgy versions of Windows 7.
The final release of the OS is expected around October 2012 so in a few months we should have the first official releases.
One question the build no. is 7989 .... aren't the build that start with 7 fom Windows 7?