Specific PC cannot get to site...

[iuchewie]

Not sure where exactly this should go so I'll start here... apologies in advance if it's in the wrong area.

I've got a user that cannot get to my site from his PC at work. The site in question is http://www.killthecan.org/

He IS able to get to the community area which is located at http://forum.killthecan.org/ This subdomain is actually hosted by InvisionFree which is why I believe he can get to this but not to the main site.

He has been able to get to the site for years prior to a couple of days ago. He did recently upgrade to XP Service Pack 3, but has since backed it out to no avail. The error he's getting is "Network Timeout"

Here's what I know about the situation

1. This problem is specific to his PC. He's able to visit the site from other PC's in his office. (the problem is specific to his PC)

2. He's getting the same "Network Timeout" from both Internet Explorer & Firefox (it's not a browser issue)

3. He's in Texas so I was thinking that MAYBE it had something to do with the storms, but then why would all other PC's in the office be working fine.

4. I looked at his HOSTS file and there are no issues there.

5. He says that there is no corporate firewall that is stopping him from going to the site.

6. He says that he's got all popup and spam blockers turned off.

7. I have verified with my host that there is no block on his domain or IP.

Any thoughts to help solving this riddle?

Thanks in advance,
chewie