Also, you should get a bootable floppy copy of "Norton's Emergency Boot Disk."

Some times a "dead" hard drive in actuality is a corrupted hard drive with a scrambled boot blocks/sectors or a screwed directory. Having Norton fix such problems can bring an otherwise dead system back to life.

A bootable minimal system floppy with Apple's Disk Fix Utility can also work for most things but does not fix everything like Norton can.

To be a Mac Tech, you need the hardware AND software tools out there in your tool box and know when to use which one over the other.