I've heard there's a few people who are having trouble logging into their accounts on this forum, which is due to Cookies. These are simple text files stored on YOUR computer with your account details, so when you come back to the site, it reads this file and logs you in automatically.
If anyone knows exactly what the problem may be, then let me know, I'm just giving some basic advice here.
Firstly, in Internet Explorer, go to the 'Tools' menu and select 'Internet Options...' then select the Privacy tab.
You should see this box (depending on your version of IE)...
Now click the 'Advanced...' button to check your general Cookie settings, the image below shows my personal settings.
You can try changing your values to the ones shown and see if you can now login.
If that fails, go to Tools->Internet Options again, select the Privacy tab again, but now click the 'Sites...' button to display the box shown below...
Here, you can add 'trusted' websites. DO NOT add ultimatejujitsu.com since the forum is actually hosted on my private server. Instead, add intelcompute.com as shown.
Hope this helps, let me know either way so we can try and narrow this problem down and get it sorted for everyone.