It doesn't matter who built it. Since you paid for it, it should include all manuals and disks that came with every piece of hardware and software. I'd insist your friend turn them over, especially the OS disk and COA.
In the meantime, you can go to the motherboard manufacturer's web site, find your board, and download the drivers you need, which should be all of them since your friend didn't supply you with the motherboard disk.