Use Microsoft Fixit to resolve the issue.
There is a whole Knowledge Base for it in Microsoft(As mentioned with Win 7 but it works for win 8)
Try Login into Safe mode.. if possible
Check also if you are using the ISO with Correct Language options
AS you are using PS/2 K/B you need to find an USB K/b available uninstall the K/B from Device Manager with an alternate USB K/B attached.Then scan for Hardware changes it will automatically detect your PS/2 K/B and you can give this USB K/B back from where you bought it (be it from a friend..)
It is a BUG in Windows 8 RTM edition that is causing the issue as per the discussion at MSDN also
he power management for PS/2 devices has been change for Win8 and hence the bug
The whole detail about the discussion can be found here