She (judging by the nice flowery writing) must be a recent graduate from university too. In older times the ram didn't duel but were inclined to work together in a dual fashion.

It may not be a faulty HD, even more unlikely to be if it has one of the super quiet and reliable Samsung drives in it.
Since most times they'll have an optical drive plugged in as well, the bios should detect that but hasn't.
I'd be tempted to reset the cmos/bios and try again. Any failure there would be a good excuse to upgrade the motherboard/cpu, pentium 4s were only good as heaters anyway.

LOL - not quite on the mark there, Jim. Maureen is in her mid-60s and nudging retirement. Upgrading the PC isn't really an option for her at the moment, but I will try the other suggestions. THANK YOU.