1. Thank you, Profman, for posting the response.
2. Near simultaneous onset of failures. So, what occurred that would cause simultaneity?
- Virus? As you say, unlikely.
- Netscape? likewise.
- "Has Microsoft put in a patch to de-stabilise NS4.8?"
-- Doubtful that they would target NS and 4.8. But:
--- Do your systems have Microsoft 'Automatic Updates' enabled? Is it possible that some fix/patch may be triggering this behavior? The August updates are indexed
here. You can find the updates for other months by manually changing the date in the URL. If you think this likely, you may wish to back out the changes, if possible, in a process of elimination.
3. For the locations of the files in the various operating systems, see
here. Note that the folders are hidden, which is probably why you couldn't find them. (There are parallel articles for the other Mozilla products, if you are interested. See the top of the first paragraph.)
Edit additions to (2):
Do you use the same anti-virus program on all the computers? - Which one? - Did it change in this time frame? Is there any other anti-malicious-email application that was installed or changed at this time?
The initial post says that mail "collapse[s] every time I use it "
- So it crashes on 100% of the attempts, and for all computers?
- It is conceivable that some particular email that all computers have received or sent has been corrupted in some manner that has induced this, although I don't understand how. You might see if it helps to delete all the mail
.snm files (Inbox.snm, Sent.snm, etc.). Netscape will rebuild these summary files as needed.
- Along the same line of thought: Is there any 'common email' that may have some attachment with embedded code or script or executable?
"With XP, NS4.8 just suddenly vanishes when trying to download messages, write messages or just read old messages. Occasionally when just sitting there not being used. With Vista it does the same, but announces it has a problem & must close, rather than just vanishing."
- Is Mail set automatically to "Check for new messages every xx minutes"?
Do all your computers use the same ISP? - Who? - POP or IMAP?
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.16) Gecko/20080702 Firefox/2.0.0.16