Roon is a very easy way to get those digitized CDs into a listenable format. A server is easy enough to make. You could use ...

Today, an internal CD-RW (read-write) drive for a desktop PC costs less than $100. It will copy a full 650-MB CD in about 20 minutes and copy music from audio CDs.

If you've got a bunch of files on your old PC that you want to transfer over, there are multiple ways you can do it fairly easily with hardware & software.