Bug#273413: apt-get destroyed hard disks
lde is the low level tool you want. But it cannot help if even
the bios do not see the drives.
I don't think that sector 0 matter regarding BIOS detection. I m
not an expert though, but i would check cables , power and such.
Also the title is misleading : apt download files and decompress
them, it know nothing about the drives and cannot mess with
The only tool changing the boot sector is grub or lilo and
whatever it does it cannot mess with bios detection.
(in fact bios detect cdrom drives taht have no sector 0 when
there is no disk and HD can be detected even if nothing is
installed on them.
Are you sure you did not kicked the box in the run ?
ou should try a livecd rescue, knoppix or linux rescue system
(smaller but in console only).