Check out DSLreports.com and go to the TWEAKS section...run a tweak test and then follow the instructions for downloading/using Dr.Tcp...one major problem is that you have to set some values in the windows registry to allow more info to flow at any time...called MTU...
I had the same problems..
the tweak test should give you a fairly decent indication of what you need to do as well as how to fix it. Might also be your location/distance from Telco office, the line in your home, etc...
