Keywords: GRO Loader & Microsoft .NET Framework 4.5 Beta
btw, my log: http://pastebin.com/yU71Bk0a
The second driver you tried is a beta driver for Windows 7. Trying to combine a BETA driver for Windows 7 with Windows 8 is just asking for even more trouble.
Yes, Windows 8 is similar to Windows 7 but there ARE some significant changes when it comes to drivers for devices (there always are). If there weren't, Nvidia and AMD wouldn't be making Windows 8 specific drivers and would instead just create a generic Windows 7/8 driver package.
You're combining preview, beta, and other untested software and drivers into one enormous pile of instability and expecting it to work.