Extension Cables

HI everyone, I am having issues with my internet speed, and consider this is due to the fact that I have a filter inserted into my master socket by the cable to my modem is an extension cable of which runs the whole way up the stairs to my PC meaning that I am not getting the full speed I need, i have also tryed replacing the cable but no joy. Any advice?

[blasted]

Yes BT have come to my house regarding slow speed and it was me due to carrying a large cable all the way from my bottom room to the top of my house.

Best bet it to email your ISP there isn't really alot you can do.