Your internet bandwidth speeds are pretty close to DSL. Not superfast but much faster than you are describing. Im guessing your problem is in your computer. You either have virus's or so much spyware, your memory is being eaten like piranhas on an uncooked McDonalds Quarter Pounder with cheese. Your registry is toast. There is an outside chance your ethernet card is bad or the drivers need to be reloaded. I suggest you save your important files, format the drive and load a fresh copy of windows.
Later