1. why can't I use the old ID?
2. why is it, when it DID work, I had to keep re-signing in if I took too long typing my post?
3. why are the signatures gone?
1) Make sure cookies are enabled on your machine... Check under 'tools>internet options>advanced'
2) Cookies have a limited lifetime, so the cookie is no longer active after a certain time period... This may be whats causing you to log off after a while.
3) The adminsitrator has probably turned off signitures altogether.
I may be wrong... But this is the way I see your problems.