403 Forbidden error

I just updated to new Firefox and I'm getting 403 Forbidden error saying "Additionally, a 403 Forbidden error was encountered while trying to use an ErrorDocument to handle the request." I tried Opera and the Explorer, it's a pain I can't access some links. I tried to download the new Hijack This but cannont access the page. All of the links on "403 Forbidden Error" on Internet lead to nothing! Can anyone help?

If you just update something, and it breaks, back up! Do a System Restore to before the update. Then make sure your system is updated and working properly, and not infested with malware before attempting the update again.

Thanks for that Digerati, I know I'm a bit of nob every now and then, I think that's hereditary! However, I'm sure I'll do it next time, now I need to resolve this blasted error, can anyone help?