Hi NielsD, when updating the BIOS we usually recommend incremental updates; you may skip few versions (two or three perhaps, depending on version number) but it is better to continue doing the update in increments in order to avoid this type of issue. The Intel® 6 Series motherboards have specific update instructions that were also discussed here: https://communities.intel.com/thread/30813
Considering the description you provided I believe the only thing left to do is checking if the motherboard is still in warranty so you can contact Intel® support for replacement.
I am truly sorry for this experience and inconvenience.
Thanks for responding.
I just made contact with support, but unfortunately the motherboard was bought in March 2011, so warranty is two months overdue.
In the release notes there as several references to BIOS 0151, but I cannot read from it that this is a MUST HAVE version (as I now think that I know).
For future improvements of release notes I'll suggest that this is added to the text.