In OE 6, Windows 98, the entire contents of the Inbox just vanished after
restarting computer. There were about 4 weeks of e-mail in there.

Other folders do not seem to be affected.

I looked in the Outlook Express folder on my hard drive, and the Inbox file
at this address:

C:\WINDOWS\Application
Data\Identities\{9226D728-E116-11DA-8D61-00045A5FABE0}\Microsoft\Outlook
Express

was down to something like 130 KB, containing just a lot of unreadable code.

I normally move Inbox contents to other folders regularly to keep Inbox from
getting too large.

I've never seen anything like this. The contents of a huge file simply
vanishing.