TexasJohn & others,
I can tell you that in almost 99% of the cases, this random logged off problem is due to some setting that is either erasing cookies or blocking cookies.
I use Firefox myself and do not have to re-login for many months. If I run some of the "tune up" or "cleanup" utilities, I often "lose" my cookies at TBN and elsewhere.
It may be a setting that is imposed along with a "freebie" or a Windows auto update; or an anti-virus program, or, who knows???
Upwards of a half a million people regularly come to TBN each month and log in automatically without any problem. If everyone wa shaving the proboem, we would have heard about it from more than a few people.
Also, you could check your IE or Firefox cookies settings, just to make absolutely sure you are not "clearing" logins at each exit from yuor browser. Even though you "think" it is not happening, some obscure program may have changed the setting on you.
Then you want to un AdAware of Spybot ro one of the crapware utilities.
I truly wish I could be of more help. From time to time almost all of us come across one of those dad-gummed problems that we just can't seem to fix.
You should also take a look at your "Load on startup" or "Run at startup" programs, because there may be some utility starting that does not show itself, and works in the background to dump you out.
Hakim