We only have a few Core2Duo and prior laptops left at the shop, office and home but as they fail we do not fix them. We feel they did well to get this far and shop for replacements. At the office we stopped buying new as on Groupon we snag under 300 buck refurbs all the time, Why do we do that? Repair of such an old laptop usually means finding a motherboard which costs as much as a much more current refurb.

-> Your trials and tests tell me it's hardware, not the OSes you tested with. I do find Linux can be gentle on old hardware so that can extend some use as we get Chrome, Firefox, an office suite and more so for many that's all they need.