I can access other sites, in the US and other countries, with no problems, and also Gmail and Google Docs, but not the above, nor Google Calendar. Been trying for almost an hour now. I'm in the UK and have tried Firefox and IE.

Google.com works fine for me. Calendar too.
Did you try to reboot?

Yep, I restarted my computer. As I say, Gmail is working, but I get nothing in either browser when I enter www.google.com. What country are you in?

Calendar still not working either – I now don't know what I'm supposed to be doing this evening!!

Searching via Google Toolbar not working either. Could this just be a problem with my ISP?

Israel.

Try removing your cache.
See if that will work.

Did that, for both browsers, to no effect.

Try accessing it by IP rather than by its domain name.

http://72.14.207.107

If google search is all you want you can also try FindForward or scroogle.

http://findforward.com
http://scroogle.org/scraper.html
  

Thanks! That IP address worked, and I can do searched, but www.google.com still doesn't work.

If the problem persists you may want to check your "hosts" file.
Check the modification date and any entry that might match google.

You may want to also try changing your dns.

I had the same problem some time ago. But after cleaning the cache and restart Firefox it worked.

Or try browsing through a proxy. If the problem persists, then probably is really down (and we are in some kind of apocalypse)

What about other Google websites?

Try http://www.google.co.uk/

Does that work?

google.co.uk also didn't work, but now, the following morning, everything is fine, so I think it was perhaps just a strange technical failure with my ISP. I can hear traffic on a nearby road, so I don't think it was an apocalypse (unless, it's military traffic...)

lol..
Glad it turned out fine George! :)