I think I might know the answer. Worth a try, anyway.
As I understand it, Chrome now ‘flags’ all traditional http sites as ‘not secure’, but allows https sites instead.
if you currently access PPRune via a saved bookmark, or a ‘favourite’, or a link, it could be that you are going to the ‘old style’ http site.
I’d say to try keying in the full web address, but to start with https rather than http.
i think it might work. If not, then I think updating the win7 pc until windows update won’t do any more, and then updating chrome, then updating your virus software would be my next step.
hope you get it fixed...