Id bet you didnt lose your data, just that the motherboard toasted itself. Usually if its a HD issue, you will get the Click of Death, (clicking sounds from the drive head crashing). And if its only partially bad, the pc will still at least show a bootup screen before it tries to load the OS from the HD.
Its always best to backup your data to other devices or media. It surprises me that so many people assume that any media is rock solid. I used to work at a pc place, and brand new HDs from all the major mfgs were coming back bad often. I had to RMA them on a regular basis.
I agree with you about HP. At one time they had some very quality stuff out there. But now, all their stuff is complete garbage, and wont last long. Ive seen so many dead and problematic HP equipment, that Im surprised that anyone buys HP anymore.
Rather than get another Laptop, you might consider de-casing a typical cheapo pc, and making an enclosure for it under your machine, and putting an old CRT or other LCD panel in the backbox. Typically, its far easier to repair a pc equipment than custom Laptop hardware. Also, if your LCD goes bad, its really hard to replace on a laptop...but very easy to replace a stand alone LCD panel.
Laptops are also very bad when it comes to overheating and dust problems, due to the tight shell, and poor airflow... which would be compounded with you stuffing it in another enclosure, especially on a mild.. let alone Hot day.
Of course, even with a more robust De-Cased PC, an enclosure should be very well ventilated with fan forced air running across the HD & CPU.
Finally, overall, its much easier to find an old pc around than an old laptop, so should anything go bad with the hardware, its a lower cost fix. However, if anything happens with a laptop, you also lose your display... so thats double the cost. Laptops, even used, are more pricy. And then theres problems with components that fail over time, like batteries. (some which are dangerous should they overheat.. or are exposed to too much vibration, can actually explode / catch fire)