Lost some internet access

For a long time, I have had both Internet Explorer and Firefox active
on this XP SP3 machine. Suddenly, out of the blue, clicking on some
web icons produce no responses. My first thought was that I had lost
my internet connection, but that proved not the case because my
Outlook Express and Eudora email apps still respond and work, as does
Firefox and this Forte Agent. However my Internet Explorer and Gmail
icons do nothing. Same for other internet shortcuts I have, such as my
desktop shortcut to Craigslist. I have tried re-installing a fresh IE
ver8 download (via Firefox) with same result. I can manually enter
URLs in Firefox to get to internet sites such as Craigslist, but what
a bother. I went to folder optionsfile types and changed the URL
therein from iE to Firefox. All that did was change the displayed
icons for my internet shortcuts to Firefox, but they still do nothing.

I have tried searching for this problem, using Firefox/Google, but I
am hit with so many exasperating popup ads, some of which block
skipping, that I gave up on that.

So - what to do now? Maybe I have a virus?

Xie Xie
Wei