If you let us know the username with a problem we can look into it. Please send requests for assistance to
[email protected] and then patiently wait for a reply. We do eventually get around to dealing with all admin mail but as we have day jobs that can take us away for protracted periods, it may take a bit of time.
Only reason that a Username loses some privilidges is that it has been moved to a different usergroup. As 'registered' you should have no problems. If you have changed your email or password and not acknowledged the confirmation email you are in the 'Users awaiting email confirmation' group and if you don't confirm within 10 days your Username is deleted. If you have been banned then you can only read the forums. 'Banned' should appear under your name in any posts you have made.
The problem with those who appear to be logged in but when they come to post is due to a corrupted cookie. If your cookie is getting corrupted regularly then you need to find out if anything on your computer is conflicting with it. The soultion that works 99% of the time is to elete ALL cookies associated to
www.pprune.org AND pprune.org (some may have the www and others may not). Once the cookies have been deleted you should quit your browser and then relaunch it and then log into PPRuNe.