It sounds like you meaning that you're loosing your login during the same browser session.
One place to start looking to see what's going on is to look at your cookies while you're logged on. Search for D-90.com. You should see at least cookies named bbuserid and bbpassword.
Then when you get logged out check again to see if they are there.
If it's happening between sessions, do you have your cookie setting to delete them when you close your browser? It should be until they expire, or you should have a white list.
Also, if you're having the issue at work, it might be due to something on your machine that deletes cookies periodically, or doesn't let them be written at all.
Four wheel drive allows you to get stuck
in places even more inaccessible.
62 88 Regular
67 109 6cyl NADA x2
74 Lightweight - The Antichrist
95 DI 5-speed
95 D90 5-speed
97 D1 Automatic