Then this is not good. It was partitioned with sda1 for swap, sda2 for root, and sda3 for userfiles. Where did the partitions go?
sdb is the external Seagate.
And why is the loss of power so destructive?
Something more than a simple loss of power is involved if entire partitions disappear, yet others remain. File systems can be destroyed within a partition, or a partition table can be destroyed, leaving the file systems intact, but then
all partitions disappear. I would run
testdisk on that hard drive to see if it can discover and repair the partition table. At this point you have nothing more to lose by trying, and just might find your data intact if you can get a proper partition table reestablished. You can run testdisk from the
liveCD.