OK, are you running any parental control or similar software...net nanny for example...that may even have been installed years ago..........
Have you checked your browser's Content Adviser settings?
in IE for example:
Tools>Internet Options>Content Adviser>Enable>Approved site>type in the approved site>allow this site>OK>etc

Have you checked that you have no restrictions that would cover this site in your software firewall?
Have you checked that you have no restrictions that would cover this site in your hardware firewall? ( within your router)
Regards
paws

My computer is only a few weeks old, so no old parental control programs are a concern. Content adviser is not even enabled (I checked). I have been searching in vain for a blocked site list in my Norton Firewall product, except for phishing sites, and it wouldn't be there.

I assume it isn't the router's firewall, as I still wasn't able to access it when I bypassed it and hooked up directly to the modem.

Would the proxy do the same thing as openDNS, bypassing my ISP"s DNS server?

Yes, it might be wise to double check them.

also check any other security related products ie Adaware, Spybot etc anything that has the capability of blocking...check
You could also disable your software fire wall for a quick test as the hardware firewall within most routers provides incoming protection.
As your machine is only a few weeks old a system restore back to just before the problem began is worth considering...
Regards
paws

I just turned off the firewall, and I still was unable to access it. I don't have anything else installed, except Hijack this.

I just did a system restore because of an MS Works update problem, to a couple of days after I bought it.

Thanks for the many replies! I know your time is valuable.

Hi you are welcome,
did the system restore do the trick?
Regards
paws

No, it didn't fix it.

:-(

Have you tried OpenDNS ?

You are not the only one computerwannabe. I have the exact same problem, on both my desktop and laptop. The guardian is the ONLY site I cannot access on both computers. And, like you, I can access it via localbypass.com.

I am in the UK, and BT is my ISP. My best guess is that the guardian have boosted security since being recently hacked into. Either that or the ISP is the problem.

If you sort the problem out computerwannabe, please let me know how you did it. And if anyone else has further advice, I'd be very grateful.