Wierd internet connection problem

[WeiWei]

I have an SP2 desktop connected to a D-Link DI-624 wireless/wired router and my problem is as follows :

My machine says that I am connected, my MSN and ICQ can connect and chatting is not a problem, I can see the network and access it.

The only thing I cannot do is open a webpage, any webpage. Occasionally, I can only open my college webmail page, and when that happens, that page would be fine. I can read my mails, delete, the works but when I open a different page, then it would fail.

Why ??

Sometimes, disabling the network card and reenabling it solves it, sometimes I have to log off and sometimes restart.

I've also noticed that this problem usually happens when I leave the machine idle for long hours. When I get it to work, then its OK, until it hits again.

There is another notebook on the network that has this same problem. MSN, ICQ, even Skype is fine. Just the damn webpages..

Please help.... anyone !!

Thanks

 

[WeiWei]

A little observation update... I have ZoneAlarm installed, and when I disable it, I can connect, then I reenable it, then its fine again..

When it didn't work, I tried running PingPlotter, but it said cannot resolve host.

Also, I found that I can open pages hosted from my university when others wouldn't open.. why ?