Computer Freezes when loading web pages

I have a Sony Vaio running Windows XP Home Edition, and
my computer will hang/freeze now and then when loading a
web page. It doesn't matter whether I'm using I.E. 6.0 or
Netscape 7.0.
Cursor sits frozen on the screen and the keyboard/mouse
become instantly useless, forcing me to re-boot!

I connect to the internet via a surfboard high-speed
modem cable connection.
I have never had a system freeze when working off line.

Has anyone else experienced the same kind of problem?

Any helpful feedback would be welcome.