I'm putting my money on the 32-bit XP limitations.

XP allocates 10% of drive to recycle bin, but there's also a 3.99GB limit on that. No idea if that's a factor or not in this, but it's fun to speculate. Anyway...as you say, if the systm is working, best not to tinker too much.

Oh and Speccy just crashed at trying to interrogate the RAM

What does Everest tell you?

that gets it right