I bought a PC from Curry's in something like 2005 for £350. It was Windows XP and I bought it because the CPU (Intel Core 2 Duo I think) was a high GHz (3.2 I think). I didn't even know what the GPU was... in fact I don't think it had one, I was probably impressed by its "integrated graphics" which actually means it uses the motherboard's, which will be quite crap. The PSU (or more likely a capacitor in the PSU) popped and died some years later from seemingly a surge, but didn't actually take anything with it or go up in flames.
The running theme seems to be the PSU is some crap quality and it isn't even named, because buyers aren't looking at the PSU. The CPU's some non-overclockable Intel with a good-looking speed because buyers don't know about overclocking or cores, and with a noisy cooler too because they don't know it actually has to be cooled and just assume PCs have an aircraft hum to them because they're beasts.
But back then I wouldn't have been able to build one (I didn't even know you could). I did an IT course at Oxford's college and the walls were made with asbestos and had holes in them, and the tutor told us the CPU can't be changed in a PC, so that's what I had to work with... Nowadays people can ask easily on forums or Google it, on their phone, and get a rough if not perfect idea on what to get.