GT-I9000 deleted messages, contacts, memos, reset preferences, etc. overnight

Hi, sorry but I don't really know where to put this topic because I don't know what originated the problem. Yesterday I was using the phone and it was working perfectly.

Today when I woke up I noticed the applications where ordered alphabetically, instead of the install order as they were before. The home menu was also organized differently. It no longer asked me for a pattern when exiting standby, the native samsung video player didn't work (but the music player did), all my memos had been erased, along with the contacts stored on the phone (SIM contacts were still there, but I have no idea which were on the SIM and which were on the phone) and all my SMS message threads, which had some incredibly important messages on it.

The SD card seems to be functional, but it's almost like the phone did a factory reset of only some things. Apps are all still there, but most of my preferences in stuff like sound and alerts are gone. The alarms I had defined are still there. It's like SOME of the internal memory went berserk or something. For example, when I entered the Gmail app, I was greeted by the welcome message, as if it were my first time using it.

I really wish I could get help in identifying what happened here. Those messages were really important, as well as some of those memos. How could the phone delete those on it's own and overnight?! Could they be locked in some part of the internal memory that the phone can't access for some reason?

I'd really love some help.

Thanks.

Problems started back up. This morning it re-deleted contacts, msgs, etc and video stopped working again. Plus, this time the phone no longer locks. After pressing the power button to turn of the screen, touching any button again gives you full use to the phone without inputting a pattern/password/pin. Any one know whats going on?

Hey, I haven't been able to solve it yet. A week ago I did a factory reset of the phone and it seemed to work, for a while. Yesterday, it happened again. Since no one on the forum provided any help, my only option is tech support, though I doubt they can fix this without a new phone.

Same thing happens to me, like everyday. And it all started from the New Year's Eve. It happens during every single night. When I wake up in the morning, everything's deleted again. All contacts, messages, notes, history of everything. It wants to accept all Terms and Agreements once again. And it goes on and on every morning.

And I charged the battery full before I went to sleep. Six hours later it was completely empty! HOW?

Have you found any solution for this problem? Please notice me if you have.
Thank you so much! 

You should reflash the ROM.