Unfortunately, I have a 'folder question mark' icon when starting up my 13.3 MacBook Pro Core 2 Duo 2009. This is what I've tried. Taken the drive out and verified/repaired permissions. Attached the drive externally via USB, booted from it and it's working this way. PRAM reset SMC reset Tried multiple 2.5 HDD in the machine, and none boot. I've even replaced the HDD, IR and Sleep LED cable, still nothing...! I'm worried the logic board is the problem, but since the machine boots with HDD externally, I feel that this may not be the case. My next attempt will be to take out the optical drive and install a drive in place of this instead... Any help or advice appreciated. The machine is out of warranty so I'll try anything.