HELP ! Browser disaster !!

HELP, I NEED HELP !!

Last night I used my computer everything was ok, and today, all
browsers except Google Chrome suddenly can't be used anymore !

My computer has a 4-core CPU, with 4GB of RAM, running XP Pro, and I
upgraded it to SP3.

I have IE, FF, Opera and Google Chrome in my system. Normally I use
IE, but from time to time I do use other browsers as backup.

However, everything changed this morning.

Suddenly, every single browser, except Google Chrome, can no longer be
used.

I clicked on IE, nothing came up.

Clicked FF, still nothing.

Click on Opera, same, nothing.

Check under Task Manager, they are there, eating up a lot of CPU
cycles (80% of 3 of the 4-cores)

Then I click on Google Chrome, it works !!!

I even re-downloaded new copies of IE, FF and Opera and re-installed
them.

Still no use.

I downloaded Dr. TCP and also TCP Optimizer to check if anything is
wrong with the TCP setting, no problem so far.

I mean, if Google Chrome can run, TCP must have been working, right?

But still the other 3 browsers aren't !

Can anyone tell me how to diagnose what is wrong?

Please help !!

Thank you !!