Consistantly go to 0 kbps when I try to do anything

This has been going on since the huge update now four times ago. I have reformatted hard drive. Bought new ethernet card like i was told by support. Cable people checked all lines and get 10000 kbps download speed and 1100 kbps upload speed with gamers internet. Had a diagnositcs run by a computer technician on computer and had them check all firewalls for sl access. All outstanding. Use sl site to check kbps speed it says awesome. Haven't had attachments on since that update cause I can't like i was told to do. I can not do anything but type and walk. Any suggestions would be greatly appreciated. The cable guys went to many gaming sites with high graphics and the only one with the problem is SL. thank you