Aurora ALX Reset its BIOS by itself

Tonight, my Aurora decided to reset its BIOS. Here's the chain of events:

After months of sudden freezes (which could not be diagnosed, no errors, no heat spikes, no "after bios health checks" could catch it) I cleaned up everything,  - got a new HD, installed a fresh Win7 64 bit, updated all drivers, disabled Alien Fusion, removed all external USB devices, save for the keyboard and the mouse and my sudden freezes seem to have went away. More about these freezes: when it occured, it was sudden, no BSODs, nothing in the event log, just a non responsive PC with a perfectly fine looking, but non-responsive desktop.

After the cleanup, I enjoyed two weeks of freeze free operation. Then about 10 minutes ago, my computer froze again. And I cried "oh darn it, not again!". And rebooted the machine. But this time, as opposed to rebooting, it showed the attached screen. Just be sure, I turned the PC off, waited about a minute and turned it back on again, yeap. BIOS was reset.

I took this picture, then went into BIOS setup. Date, Asset tag, everything was reset to 0 or NULL. I reset the date, could not touch the asset tag - of course - and reconfigured the drive controller (RAID) and the workstation booted normally.

I am pretty sure that the freezes and this is very closely related. But how? And what do I do now? I believe this thing will happen again tomorrow night, or whenever I reboot this thing.