I think that the blue crab icon programs could possibly have been authentic Realtec audio drivers
Unless you do a low level format a boot sector virus would survive, I think that you may be able to do a format followed byfdisk /mbr but you would also have to delete any partitions that had been created, a popular place to put nasties is on the recovery partition, sneeky!!!
Prolly right, there again I don';t do Windoze and haven';t done for a few years Linux is the way - so that might explain why