Fast internet, VERY slow streaming!! PLEASE HELP!!

Hi, I have a VERY annoying problem which i've been having for a while and it's at the point where I want to throw my laptop out of the window. My internet speeds are good and I can download very fast with speeds like 2 megabites a second downloading. On Speedtest.net, I have 18.85mbps and 1.1mbps uploading speed.

Yet when I stream something from ITV Player or 4OD (And sometimes YouTube), it plays for one second and then stops for 3 - 4 seconds, and then plays for a second and stops again. It's VERY annoying and I don't know why it's happening.

I have Comodo free firewall (Windows firewall turned off), and Avast anti virus. Although even when I turn them off, streaming is still awful. I use Mozilla Firefox regulary yet it does the same on Chrome and Safari. I always update Windows Update and Flash Player and don't have anything downloading in the background. I've deleted all my temporary internet files and used Spybot and deleted everything it found, yet it still proceeds to be very slow.

I reinstalled my operating system about 3 months ago to see if this was the problem yet it still proceeded to do the same.

Please someone help me with this before my laptop hits someone passing by when I throw it out the window.

Thanks.

 

Wired or wireless? If wireless, 2.4ghz or 5ghz?

 

Does this happen when the video is fully buffered (the grey bar fills in the Youtube video progress bar)?

 

It's an Ethernet wired connection.

No, when the grey bar fills the youtube bar it plays. Although it takes ages for it to fill it sometimes. I usually have to change the quality to 360p or 240p. And on ITV Player and 4OD (Popular UK TV streaming websites) It doesn't buffer, it just kinda live plays. I could leave press pause, leave it on for hours and it doesn't 't buffer.

 

Sound like router problem?
eh stupid me, but then he is on Ethernet -.- so not wmm.