My Mac won't load certain pages

Hi there, I was wondering if anybody could help me.
I have a iMac OSX 10.5 and it blocks more and more pages. At the moment these are some of the pages I can't view:
deviantART: where ART meets application!
MONOmoda.com
eHow | How To Do Just About Everything! | How To Videos & Articles

I have checked firewall, clearing DNS cache via terminal doesn't work either.
The pages work on my laptop and i have to turn on the laptop on to view those pages.

Please help with this issue

You don't say which browser you're using, but assuming you're using Safari: have you checked Safari -> Preferences -> Security and are all the Web content check boxes checked?

Other than that, I can't help.