After all this I am still running into issues even though I thought everything was fixed and I've tried most everything I have found, though not everything. All I can say is that I've pretty much come up with the fact that it is the .NET Framework that comes with my OS that is malfunctional. I ran the methods listed here as well: http://support.microsoft.com/kb/976982 on top of doing everything that was listed in this thread.
So I am still left with the question if there is any definite way I can un-install my current Framework from my OS even though it came with Windows 8. Or perhaps there are some Windows 8.1 clean-up tools that are available or something like that.
I have managed to get a few things working, though, and I made sure that I fixed that CNBJ2530.DPB" of prncacla.inf issue because the sfc/ scannow command tells me that there are no issues, but I did not make another text document to see the results. One thing I got working was GeForce Experience all though it doesn't run as fast as it should. I start it up and it takes 20+ seconds to start, followed by a " unable to connect to nvidia try again later" message, followed by the program starting up. But I should be able to download drivers in the program and I can't because it keeps telling me to check internet connections, but I can download drivers from NVIDIA's site perfectly fine.
Apples....
Is it a PC or a laptop?
If it's a laptop, you cannot uninstall 8.1 which would be the only way to remove .NET 4.5.1 since the latter is only installed when you upgrade to Microsoft's latest incarnation of Windows.
And I've just read that the8.1 upgrade destroys the manufacturer's Recovery partition so that you can no longer use it to revert to Windows 8.0
If it's a PC and you have an installation disc, then you can reinstall Windows 8.0 again , sort out your .NET problem and then upgrade to 8.1 again. The latter will include .NET 4.5.1 of course and might place you back in the same boat you find yourself in now.