Widow 8.1 not shutting down properly

I installed Win 8 Pro 64 bit on an SSD in a new build PC, this was upgraded to Win 8.1 and the latest updates installed. Now when I click to shut it down the screen very quickly turns off followed by the SSD light some 20 seconds later. However the power on light remains on and the PC is totally unresponsive. It will only restart after powering it off at the wall socket, I even tried leaving for a few hours.
One day on start up, a strange home page appeared, this prompted me to run Malware Bytes Antimalware, which found more than 200 malware items. This surprised me as an antivirus prog is installed and the firewall is activated. I suspect that the pc is running all the time with only the display and the anti virus software switched off.
I have searched the net for a solution only to find that many others also have this problem, while many of them have found a solution these don't seem to work for the other complainants. I too tried some of these without success.
I should say that the initial Win 8 Pro 64 bit installation worked without problems, which only surfaced after the last updates.
Any Ideas on how to really fix this, or should I switch to Win 7 Pro 64 bit, which I have?.

 

Sounds like your computer may be infected with some type of malware, (malicious software). Recommend starting with these instructions and then posting the requested log(s) in our Malware and Virus Removal forum.

After your computer has been given a clean bill of health by one of our malware experts, if you are still having the same issue then please return to THIS thread and we will pursue other options to help solve the problem.

 

Thanks for your suggestion but I have decided to revert to Win 7. Maybe i will try Win again if it is further developed. Or maybe even Ubunto!

 

Nothing wrong with Win 8. You had a problem with your PC such as what was suggested in post # 2. Malware/Spyware. Why go backwards?

 

Each PC is different. How do you know you had exactly the same thing that all them others had? MBAM and your AV lots of times are able to get rid of everything. There are other programs that can be run to do such.

 

You mean you have decided to set your computer back almost 5 years (since W7 will be 5 in October).

I agree with MrBill - there is nothing "wrong" with W8. There is a bit of a learning curve, but it is not hard to make W8 look, feel, and behave like W7.

Windows 8 is more secure (reason enough to use it) and faster than W7.