Bargain download machine setup?

[pratstercs]

I want to build a mini pc solely to be a 24/7 download box, to replace my old laptop which did the same job. I want it to be quite small, and the only requirements are that it has to be able to run some version of windows, have a fast LAN connection and have a psu of less than 100W. My budget is REALLY small (~£50/$80) but it doesn't have to be good at all.
I have spare 2.5" HDDs from my old laptop, so they're not a problem.
Any help?

 

[batuchka]

Hmm at such low price points and rudimentary needs: consider a used set up perhaps?

 

[pratstercs]

Is there a name for this type of system? I've looked but i can't find what I'm looking for.