IE 7 on WinXPP-SP2

I am running WinXPP-SP2 and IE7 with all latest patches/updates. I also have Firefox installed (also with all latest patches/updates).

Default web browser is IE7.

Lately (may be for about 10 days or so…) more often than not, when I click on techrepublic discussions, IE7 will error out saying ‘server not reachable’. But when I copy the URL and paste it into Firefox, it works.

Any idea/pointers, as to where/what I should be checking?

I know I can make Firefox default browser, but IE7 was working fine up until the problems began and I do not recall changing any settings in IE7.

TIA.