Very quickly...
1. Without IE your 3rd party browsers would simply not work in Windows so upgrade IE even though you may not be using it to version 8 from here:
http://www.microsoft.com/en-us/download ... tails.aspx
2. Install Windows SP3 if you're still on SP2. Restart at the end.
http://www.microsoft.com/en-us/download ... aspx?id=24
3. Use IE8 (only) and log onto this site:
http://www.update.microsoft.com/windows ... e&ln=en-us
Now select CUSTOM and "scan/Install" any security updates offered.
NB:1 If a "Root Certificates update" and/or KB971029 is listed in the "Optional Software updates" category on the left-hand side
of the scan results window, install them.
NB:2 Don't install any other optional software updates nor hardware updates.
That's it.

Bye!