This looks exceedingly close to it, Rotorcraig - if you don't hear any more thanit has fixed it. Thank you!
However, M$ are not issuing the fix online, you have to request it
It's actually easier for me to use Firefox, for pprune and any other site that doesn't work.
Edit: this seems to have done it; I used the "workaround" described in that M$ page of disabling HTTP 1.1 (whatever that is?) since I can't be bothered to contact M$ UK to scrounge the fix from them. Presumably it is a new Urlmon.dll file dated 4/8/2006 - does anybody have this file?