Connection Speed (possible malware)

I get correct results from speed tests. I tried downloading things using my mobile phone using this connection and everything seems correct. But when i try to download something using my pc it gets a 50kbp/s max download speed. Malwarebytes, Avast and SkypbotSD2 detected nothing.

Do you have Malwarebytes, Avast and SkypbotSD2 all three running in real time ?
Is/was there another av on the system?
If so which one and how did you remove it?
What windows version?
What exact avast version?

I have Avast and SpybotSD2 running in realtime. I only use Malwarebtes for ocasional scanning.

Windows 7 Home Premium 64bit
Avast version: 2014.9.0.2021