Log in problem for new user

I am using version 6.32 of Webwiz forums. I have been using this forum software now for 4 years and I'm very happy with it and don't want to upgrade to a newer version, so please don't offer that as a solution.

The problem is this: I have a new user who registered on my forum. I have my forum set up so that Guest accounts and newly registered users can read the forum, but not post messages. Once they email me, I will upgrade their access and they can post messages. (This was to lock out spammers.)

This new user registered, I upgraded his account, but he says whenever he tries to log in with his username and password, the forum still says Welcome Guest, and he does not have posting access. He receives no error messages, he is just considered a Guest. I have checked that his access raised correctly, and he has Java and cookies enabled in his browser. I had him re-register again with another account, raised that one, and the same problem occurred. I had him go to another web site that is also using version 6.32 of Webwix forums and try registering on that forum, (not run by me) and he said he had the same problem there.

In 4 years and over 1,500 users I've not had this problem before, so I'm thinking it must be something on his end, but I'm not sure at this point what he can try or how we can find out what the problem is.  He is using IE6 with Windows XP.

Thanks! I told the user to clear his cache and cookies and that fixed the problem. All is working well now.