norton bootable recovery tool

a buddy drops off his mom"s computer for me to look over.  turned it on and everything i tried bsod.    i downloaded norton bootable recovery tool on my clean machine to a flash drive.  put it in infected machine, loads right up and we are off and scanning.   detected boot.tidserve   and 2 other trojans.  repaired the trojans but could not fix boot.tidserve.   the recovery tool was so easy to use and performed well its just a shame it couldn't repair the mbr.  i still have the blue screen.   thanks