More likely it was the begiining of your HD Failure that was causing things to blackscreen.
Here is the summary: HD only reads the first few blocks on POST (Power On Self Test) then stops. HD cannot be autodeteced by BIOS. The HD is 9 years old, and ran every day for 12 hours. That's 38,000 hours. Not much at all for today's HD's with an MBTF of multiples of that. But it's pining for the fjiords..
Data can be recovered by getting an identical drive and under cleanroom conditions, switching the platter stack. Software recovery and repair programs like Spinrite will not work if the HD will not run.
Not sure ow you arrived at that...I might have missed something...
but I thought the last difficulty was that she was not seeing a BIOS screen...which to me would indicate, one of a)keyboard problem b)monitor problem C) motherboard problem