Batteries flat quickly? Do you have wireless mouse and keyboard?
I'm unconvinced that the HD itself has failed - 3 times! HDs have their limits but on the whole are very reliable.
Certainly there is serious trouble which in my view has not yet been found.
Years ago (in the days of W98) I bought a new budget computer for a son.
The deal was that I was supplying the OS and software.
I couldn't get beyond the earliest parts of installation. Formatting showed increasing numbers of bad sectors.
Mercifully the supplier was Novatech. They posted a replacement HD twice before asking for the whole computer.
This time they installed an OS and then wiped it because I wasn't paying for that.
No more trouble through the years we had it.
Very sadly I was never given the cause of the trouble, but faulty memory may be one culprit.
Motherboards do sometimes betray. If either of these are corrupting the codes fed to or retrieved from the HD, it will garble the contents of the HD.