Well now this is a totally different situation...
I wished you had stated that further back as it would have eliminated speculations about your computer. 

OK, if your monitors are plugged into your interface and your interface is turned off you still hear a sound, correct? 

Is it quieter than with the interface on? 

OK, unplug the USB cable. 

Unplug the monitors at the back of them. 

This will narrow down the SOURCE of the sound.  

The only way to trace sound problems is through eliminating possible offending gear, either swap it out for something or do your best with what you have buy taking one component at a time out of the equation. 

Reinstalled Windows. No software yet. When i click the media player the noise and beep seems to be gone but i'm not getting any sound out of my speakers/octa anymore... This is so ridiculously frustrating. I would kill to use my studio for more than a week without problems appearing out of nowhere.

you have my compassion.
have you installed the driver for your device?

you have my compassion.
have you installed the driver for your device?

Thanks. Ya, i installed it. I can see it's playing music in the audio settings, i can plug in my guitar and see on the octa that it's getting input but no sound whatsoever. I removed my sub to make things easier. Monitors plugged in directly to the octa but no sound. So, the noise is gone, together with the rest of the sound...

My advice in my first post was to use a set of headphones to eliminate issues with a complex audio system,,, did you ever do that?  ( edit:  OK I see you did) 

The more you say the more I see you didn't follow a logical path yet, your stabbing in all directions at once, take a deep breath and follow the signal chain , slowly eliminating each piece of gear that could be at fault. You've certainly eliminated your computer for now. 

Just thinking, You obviously have more than one computer or you certainly got your DAW back on the net in record time. 

This is still looking like a possible defect in the octa capture as that's always been in the equation. 

Two ways to test it. 

Activate your on board sound card and see if there is this sound using the headphone jack. 

Install the Octa Capture on a second computer and use headphones to listen. 

I will test the octa on another computer. Good idea. Thanks.

I tried it on my other computer. The octa capture is kaput. No sound. Just some noise. Great, just great. Got it 2 weeks. It doesn't even surprise me. I know i can't have 2 weeks of recording stuff without something breaking down. Ofcourse i gave my quad capture away so now i have nothing again. I'm gonna have to send it back and that will take weeks before they tested it and send me a working one. Thanks for all the help everyone. I'm gonna hit my head against the wall now.

Don't get me wrong, re doing your OS would seem like an extreme move but I actually agree that it certainly is quicker than the zillion geek tricks you need to do otherwise. 

Whoops typing same time again.... see you solved it , but in a nasty way... I'll see you in the returns line up with my Behringer powered speaker that lasted 3 weeks...