Help-- How can I stop this pop-up

[Aphex]

Hey guys,
I've been suffering from this issue for two days now with no hope. I downloaded a program from this forum and then installed it on my computer ( I unfortnately don't remember its name). Then, I didn't like the software and deleted it completely from my system. The annoying thing is that there is something like a pop up that keeps popping on my desktop, not my browser, every 3 minutes or so.

I can't stop it. I know it's not a pop up, but it's very annoying. It flashes very quick like a light or a small window on my DESKTOP. Everytime I 'm watching a full screen video online it interrups the video and the whole system.
Any help is appreciated