I have MSE installed now, and fully up to date.
I also worked out how to run SFC from the Command Prompt as Administrator (google brings you to explanations as to how to, posted on these very forums by Brink).
I ran it three times. The first time is stopped at 10% verification saying 'Windows Resource Protection could not perform the requested operation'. The next two runs were fine with nothing reported.
I'll run Memtest tonight overnight. I'm pretty confident it'll be ok as I ran it 2-3 times a few weeks back and there were no issues to report.
It might be false hope, but I haven't had a BSOD since uninstalling Avast/Comodo. We'll see, I didn't get a BSOD for several days recently after updating the video driver
, and thought then too that it might just have been the fix.