Can't access some sites & Network Hangs

Hi !

I'm kinda new to this forum and I'd like, like everyone else, not to return here again !! lol :D

I have a little/big problem with my network.  Here is my configuration :

AMD Athlon XP 1500+
MSI KT3 Ultra2 (sound/video included)
Intel Pro 100M Network Card
256 RAM DDR 333

My problem is the following : When I try to access some sites like www.google.com or sympatico.msn.ca, the page begins loading but never get access to hit.  No errors, just a simple blank page with the loading bar at the bottom right of Internet Explorer hanging at approx. 50%.   It stays there forever.  It just hangs, nothing freezes.  I tried an Old Realtek Network Card and a new one (from my other PC, and on my other PC everything is running smoothly).

I'm behind a DSL Router with all ports opened (the only thing , my other PC is working fine but this AMD can't access these pages... It causes me some troubles with online games 'cause sometimes (on some games) everything just freezes like if it was a never ending lag.

It also causes me some troubles when accessing specific pages of on some websites like not showing some images etc... I tried almost everything, from updating all drivers to using old drivers.. changed network cards thrice :D  And I even plugged my cable elsewhere on the router.  I tried to use my network cards on my other PC and everything is OK.  

Someone had this problem before ?

Thanks !