Problem with 13" MBP external monitor, DVI adapter or maybe computer itself?

So, I created this thread because I tough that my adapter is faulty, or a cable. I didn't see that last time, but I got this today.

I was watching TV show on my external screen and I connected external hard drive to USB. My external screen immediately turns black. I re-connect the external display - same thing. I pull the USB out - everything works as it has before - I'm watching a TV show on a external screen... That means once I connect USB external hard drive - it just blocks the MiniDisplay port or something like that? By the way, I tried both USB's - same s***. Also, If I connect my speakers with 3.5mm jack, external monitor turns itself black for a few seconds and it gets back after few seconds. Doesn't block it like USB hard drive does.

Anyone, any ideas what is the problem? :/

 

It is 3,5" External HDD and it is powered by a brick.

I tried connecting PS3 controller - no problems with it. Charges as it should.

 

No-one?