@wqgq_641,
If you have to stick to one computer for general use and audio use, then @erik_squires suggestions regarding power supply and isolation are on point.
However, consider if you can instead sticking with the current pc for other use and invest in a dedicated network player running linux. Moving mechanical spinning discs to a NAS in another room is absolutely a benefit in sound quality, regardless of the USB/ethernet discussion. If your library is small external SSDs might be another option(although generally too expensive IMHO).
Have you read about projects utilizing Raspberry Pi with Volumio app? They sound startling good vs. most of the PC based setups I've heard and they are super affordable. With your building skills, could be a great fit! I have a friend who's built a few that I could hook you up with for any email questions etc., if you like that idea. DIYaudio has lots of coverage on them. Cheers,
Spencer