To make it quick just reinstall windows on one card only (ofc in mainboard) then install all drivers, miners etc.
If it works well, add risers and graphic cards just one by one.
That is what you should do if you want to be back up and running within the shortest amount of time possible. I think you may have corrupted your OS files and Windows is easy corruptible.
A clean install of the OS, of course by taking out any money if you happen to have your wallet in this rig, just get the seed before doing this clean install and you should be up and running to the point where you were before.
Sometimes it is also advisable to look in the motherboad BIOS settings and to enable 4G and Pciex 1.