Black Screen Video And Crashing in WMC, KODI etc

[bchase]

I was having problems with WMC so read an online thread to delete all files from
C:\ProgramData\Microsoft\eHome

Now (whether related or not) I cannot play any video in windows. In WMC all playback is on a black screen and the mouse pointer has gone. On Kodi the sound starts for a few seconds on a video then the whole program crashes. However strangely video plays fine from WMP?!

I have tried reinstalling Windows whilst keeping my personal files. However the problem remains. I've tried reinstalling graphics drivers and catalyst manager but no joy. I tried a system restore but all restore points come back with error messages. I tried a system refresh but even though I have the genuine original discs it says they are not valid... HELP!