Board Resets

[Logik]

My board seems to reset often. Everything is there, post, members etc. The only problem is, is that I'll have like 300+ members for like 5 hours, then i logg out. I come back after a couple of hours and everybody is gone. There gone from the memberslist online, but still logged on. Im tryin to figure out why it does that?

Someone help plz.

Anybody.