Yep, I've tried that. I've now put the files back in www/mydomain.com and the initial problem is still there. In IE 5 (PC) none of the pages are updated.
Safari lets you do a complete reset - getting rid of cookies, cache, and history in one go. When I do this, the page that displays when I type in mydomain.com is still not the updated index.html page. However, when I click the home button on the page that is displayed (which takes me to mydomain.com/index.html) the correctly updated page appears.
I haven't been able to try the procedure in IE 6 (PC), but the fact that the pages show correctly in IE 5.2 (Mac) suggests that IE 6 (PC) should be ok. I'm just baffled as to how Safari and IE 5 (PC) can find an old webpage that shouldn't exist, even when all temp files have been deleted!
I don't suppose anyone else has come across this problem?