Vista SP2 - Internet Explorer not working

I've upgraded my Windows Vista system to SP2. And now I find that Interent
Explorer won't work. In fact anything I run that has a link to the interent
isn't working. My network connection is fine. Any ideas on how to fix this?

Presumably you mean you fire up a web browser and cannot connect to the
internet but can connect to other computers on your network?
I suppose that is not impossible but seems unlikely.
If that is the case then under tools/internet options/connections click the
setup button on the top left.
If you still cannot connect to the internet try resetting your router
(unplug, count to 5, replug). Vista wireless connections to routers are
stable on some machines but very tenuous on others running similar hardware.
At my house two wireless Vista units never drop their connection to the
router but a third periodically requires the router be reset although the
other two units have stable wireless connections.

I've worked out that the Vista SP2 upgrade has corrupted my Interent Explorer
(I'm running IE8). I've tried reinstalling IE8, but it fails. I cannot
uninstall IE8 either, it does not appear in the list of programs for
uninstalling. Neither do the IE options appear in control panel. I've tried
unistalling Vista SP2, but that fails too.

Actually, I tried to launch IE8 several times and gave up. Later I tried this:
Right click on the IE icon and "Run as Administrator"...it launches IE.

Ok guys I had the same problem but I fixed it. The Service pack upgrade
disabled my Norton Internet service from running this in effect block me
from surfing the internet. Once the service was restarted then the
problem went away.