a few points. While i agree that the problems re likely with WMP and the PC, i want to re-iterate where the problems likely lie. Not with the simple fact that you are using a PC -- but with two things:
1. The configuration settings, some of which may be very hard to optimize
2. With the electrical (ground) noise
Both of these can be ficed, but most wont have either the expertise or the inclination to do so. On a mac you can use bitperfect and the configuration issues are solved. Gond isolation is more of a problem, although on battery power my macbookpro was more or less fine.
Many have suggested Roon. I love roon, and also hate roon. Note that you will still have the ground noise problem if you connect your roon PC directly to your DAC.
Roon has also just made major changes that i find a real problem. They discontinued support for most operating systems aside form the very atest - making most of my units obsolete even as casual remotes. They also have made it so that you cannot play your own local library unless you have an active broadband internet connection. You heard me right. So yea, its great, but its also nto the most customer friendly company on earth. This is all very new BTW. Beware.
I do think that software solutions liek Roon or audirvahna are fare more modern and long-term than some costly streamer-in-a box (which is almost certainly a raspberry Pi computer inside a fancy box with a good power supply and isolation).