I finally solved it. Decided to take a look at the back of my PC case and the sound card outputs. I guessed it right... my 2 stereo speakers + sub were still connected to the second plug which is combined headphones/stereo speakers output, with auto-switching enabled.
Instead, I plugged my 2 speakers + sub into the third plug at the back of my card, which is dedicated line out for simple 2 stereo speakers + sub. Other 2 plugs I am not using since I don't have any 5.1 or 7.1 speaker setup laying around.
Instantly after reconnecting everything, I realized audio coming from Spark using ASIO has much more definition, should I say clearer, plus all other Windows sounds (on the desktop as well as inside the browser, like for example YouTube videos), started working in perfect harmony. Finally I can watch some video tutorials online without having to shut down my Spark or any other program using ASIO.
My other question if I may... is... are there any cons to using 96000 Hz sample rate vs 48000 Hz? I've noticed a lot more organic sound when using 96000 Hz, but my question is, are there any restrictions when I am ready to record my sound to some outside source, or will this give me better sound anyway? ...or... should I simply stick with 48000 Hz?
Thanks in advance!