There's an outfit in Oakland which does this.[1] They're a computer recycling center which assembles working systems from the recycled ones. They currently offer minimum specs of at least 2GB of RAM, 80GB HDD, DVD-ROM and 17” monitor. They install Linux XUBUNTU 14.0.1. The machines are free to schools, non-profits, and low-income people.
There was a similar organization in Berkeley which installed Windows. They had a deal with Microsoft which allowed them to do this. But I think that ended with Windows XP.