[djsin421]

0 filling the hard drive is basically writing zeros to each sector of the drive
as far as i know when you buy a new hd it comes zero filled

the os part is pretty strait forward

as far as the firmware downgrade i simply unistalled everything to do with pt 7.4 installed 7.3 and when i booted 7.3 it asked me if i wanted to rewrite the firmware to the 7.3 version

this may be a mac and pc difference but i doubt it

i'm going to give my system a full recording test today and i will let you know if there are any problems still

my playback problem is definetly gone

hope at least some of this helps