Can't load a website in Windows 7, but can in XP

It could be that you don't have the 'root certificates' on the Win7 computer but you do on the XP.  This page tells about it and has a link to the page to get them: http://www.dtic.mil/dtic/announcements/dodrootcertificates.html

A. Tried that and it didn't work
B. Users of these computers can log on to some .mil sites, and not others.

and yes, I have checked the site to make sure it is working...
simultaneously you can pull it up on an xp machine and not on a 7 machine.

Then you should click on the security icons in XP to see what security protocol it is using.  There are more than one.  And there is the issue of root certificates although in Windows 7 I believe those are supposed to be automatically updated.  Are there any details to the error messages?  And can you give us a specific site that doesn't work?  I found several 'mil' sites that gave me certificate errors in Firefox on Windows XP which is why I found the certificate site.

Possibly the .mil's site certificate has expired or is invalid. Did you try Firefox on W7?  FF should at least give you a warning message and letting you choose to temporarily trust the (expired/invalid) certificate. Not really recommended of course but at least you can view the site.

Nice thing to have 2 firewalls, good to hear you solved the issue, I would not have thought in that direction.

I would not have thought of that either.

this worked