128MB is not very much memory when running Win 2000. At work when we ran Win 2000, recommendation was 512MB. So I would expect you will see an improvement in performance if you increase memory. Whether this will speed up boot time, I do not know.
You are probably loading up unneccessary programs at boot. You could try running msconfig (Start, Run, msconfig) and selecting the Startup tab. This will allow you to select which items you want to load. There are web sites which offer advice on this. Hopefully someone can provide a link.