What are the details then? Flashing the bios is certainly not the last thing to do,these days it is something done quite simply and like patching a game it can improve performance. But I do not think flashing the bios will be of much help with your problem though it would not do any harm if the mobo is knackered anyway.
The reason that the board is not listed is because it will probably be an OEM mobo produced specifically for Packard Bell. There might be support somewhere but it can be tricky to track down, so if you can post the mobo details.
From what i can tell that board was a oem specific revision of the gigabyte GA-8TRC410M-RH used in some packard bell and nec systems. As there is nothing for it on Packard Bell /NEC sites, it probably dosen't have any bios updates.