Yeah, it's possible. Just watch what you install and keep a RAM cleaner program handy.
I've run 98SE crunching SETI for nearly two months on a Pentium in the other room, was still at 95% GDI resources free when I shut it down after 50 days. 98SE has a memory leak in the same place ME does (if I remember right), so it shouldn't be very difficult to keep the OS in one piece.