Not sure if I am any further forward or not, but I did a system restore and that has made no difference. I actually don't use SR but ConFigSafe which appears to save a lot more data.

However, in searching for a solution, I found an MS 'how to' on how to reset OE. In following the instructions to re-register certain files, the files regsvr32 mshtml.dll and regsvr32msjava.dll (or even regsrv32 /i mshtml.dll) give the message ' ****** entry point not found, file not registered.'

Don't know if this is the cause of the problem but how do I reinstall and register them?