First thought "Begin with the end in mind."
That is, define the needs the device is to meet. That allows you to
determine the hardware, operating system and software required. From
there,one can add RAM and storage option upgrades, video card
enhancements, etc. and so forth.
If you examine the files saved on your friend's old computer, that
will give you a good idea of what he/she uses the device for. Add to
that the current "wish list" ranked by importance/value to the
If it turns out that an off the shelf Laptop will suffice, you'll have
the specs requisite to effectively putting out a "Request For
Proposals" or shopping pecs sheet.
Then go looking for suppliers and deals on price, quality, warranty,