Wireless computer internet speed 16mbps, wired computer 0.4mbps

I am with Virgin media and have the 20mbps fiber optic connection. My area has recently been having problems with the broadband and Virgin has recently fixed these problems. However I used to get around 19mbps now that the problem is fixed my computer which is wired to the router gets about 0.4mbps downstream... However the 5 wireless computers all get 16mbps which is pretty good for them.

I'm know a little about computers and have searched high and low for a solution. Windows tells me that its a firewall issue and I currently can't use two programs, spotify and steam. They both have firewall issues, even if I turn off my firewall which is the windows one. I also have avast, and when I turn that off, still no good. I used OpenDNS, stopped using that flushed my DNS, that didnt work. I tried to optimize my computer settings, by changing various values in Regedit (followed a guide online). All of this has done nothing.

I should add that I have recently re-installed Windows 7 so on this fresh install it has never had decent internet speed. Which I thought was weird.. I have basically had these problems since the fresh install.

So I am completely at a loss. I thought that it might be Virgin specifically slowing my computer down, but I have no idea if that is even possible and I am probably being paranoid...

Any help would be much appreciated!

Cheers