Adirondack case guy, with the new system you have to come to the exact address or the system changes how you are getting to the site. So your cookies are stored in different files because you are accessing the site from different directions. Your computer thinks that each one is a different site.
You have to have : www.yesterdaystractors.com
If you have anything else the system will get you to the site but from different ways and this causes the site's servers and your computer to store the cookies in different places. Mine would work right in some forums and not others.
It was all in the fact that I did not have the full address in my favorites.
Then in your Internet security setting you need to mark this site in your computer to always allow cookies from this site.
Drove me nuts for a week until I noticed I had the site saved as yesterdaytractors.com. Notice the lack of the WWW on the front and the "S" in the middle. That was all it took for the computers to go crasy. So makes sure you have it as: www.yesterdaystractors.com