BIOS Update and ATA Error

I recently updated the BIOS on my Dell Inspiron E1505 laptop to the A12 version. Almost immediately after doing this the unit frequently began locking up. This required physically turning the machine off and rebooting. This is followed by the message [XLDR] ATA Error. Booting the system with the F12 option and running the diagnostic reveals no errors. I have searched for a common error elsewhere on the forum and it seems to be Hard Disk related but have not seen anyone relate it to the BIOS update. Is it just a coincidence that this happened after the BIOS update or is there some bug in it?