The computer I use most of the time is a 19 year old (2005) laptop. I run Debian with LXDE and Firefox on it and, although you have to be a little bit patient with some websites, I am generally still very satisfied with it.
I suppose it's a desktop replacement model with desktop Pentium 4 and whole 2 GB of memory which cost thousands of dollars? Regular Pentium Ms of the era get dangerously close to netbook Atoms in performance, which is certainly the bottom of the barrel.