What to upgrade next.


This is my first foray into the forum other than reading other's post. I hope respondents will be kind! I am at the very low end of audiophile equipment and many of you may not think I am there yet when I list my equipment. The economy has become better for myself and I am looking to upgrade but not exactly sure where to go from here. I am sure I will receive many different suggestions so I plan on taking the one suggestion that I receive the most and employing it. My equipment is as follows: Denon AVRx 3500H as my integrated amp which is boosted by a Bob Carver Cinema Grand 5 which pushes 200wpc. This powers my Polk Audio RTiA7's which are my music floorstanders. When I started upgrading I chose the Polk's as they seem to punch above their weight. After months on this site I am unaware of many people who extol the virtues of the Polks so I am thinking this may receive the most as far as recommendations. I stream most of my music from my desktop and laptop. The desktop sounds like an airplane waiting to take off. I am not independently wealthy but am looking to spend between 2-3 thousand if necessary. The one thing that gives me the biggest headache at this point is music delivery as computers have glitches and my angina acts up when the music cuts out in the middle of Alex Lifeson shredding his axe. My music files range from bad copies of MP3s which are slowly being replaced to HD Audio files. Thank you for any suggestions.
dadork
It seems like you already have a good idea about how to start the upgrade. For $2-3k, if I were you, I’d improve the speakers, get a decent streamer, and an external DAC. Many specific product suggestions are possible, but to limn a max budget: $1600 on speakers, $800 on DAC, $600 on Streamer.  (E.g.Dynaudio, Denafrips, Node 2i). My two cents.
I would invest in a good streamer and external DAC. The Node 2i is a good place to start for a streamer. I really can’t recommend the right DAC as I have just started out on the external DAC journey. What I am using now,I’m sure won’t still be in my systems next year. 

     I would get your streaming situation figured out first,this way you have a better idea of the speaker synergy,and go from there. 
 
      Enjoy the hunt!
What is your main focus? Music? Movies? Both?

Your Denon is for home theater, movies so if your emphasis is on music you will have to do something about that.

Your ordinary desktops are not the best for streaming music unless you have a linear power supply, good hdmi cable. Computers can produce a lot of noise and like you said you have a lot of fan noise.
How are you streaming, wireless or cable?

That being said I use a Intel Nuc running Plex as a music server, though I have not done it yet I can get a linear ps and good hdmi cable for it which will make a significant difference.
I do not know why you are having the Windows glitches, I am running Win 10 with Plex and have no issues.

Your bad copies of MP3s are definitely a sticking point. And what do you mean being replaced to HD audio files? Replaced how? With what?
I rip all my music to FLAC from CDs, the MP3s that I do have I am replacing with CDs.

Will