Urgent for Users of Internet Explorer: get the Internet Explorer update ASAP.  Internet Explorer | Tools | Windows Update | Custom -- install particularly the one for Internet Explorer.  This is an out-of-sequence, emergency update followed by a Windows restart.  This fixes the problem Google had with its accounts in China.

Users of Windows XP or 7: be sure your anti-virus is up-to-date and that you have the latest Windows updates.  *** Limited Windows Vista support by MadMod Computing! ***  Use Ubuntu 9.10 or Windows 7 on new computers for safer e-mail and web browsing if possible.  See the Ubuntu Diary for details.