Hi Guys.
Thank you for your replies.
Having spent far too much time on this problem, I have now found two bits of software that do the trick.
You have to double click the SecurityTab file, then click Yes to merge into the registry
You can then see the Security tab.
When done, double click the SecurityTabUndo.reg file to undo the change.
Apparently, it's not recommended to leave the setting in the registry. It basically fools Windows into thinking it's in Safe Mode and programs or services that check that value to see if Windows is running in Safe Mode may get confused.
I've tried to attach the files to the post but failed miserably.
They are the wrong kind of snow, sorry file.