Speeds down a lot, I do not know why?

Users questions: Not long ago I rate steady at 70K (with download software download full speed), and watching network TV with PPSTREAM no card, but recently suddenly find full download speed down to only 12K (tested with a test software), it is strange. In addition to complement the recent installation of WINDOWS D, were also not done any adjustments and may interfere with other software installed, do not know whether this relationship is that the system set up with error. I am using a wireless router and not previously happen.
Experts answer: my old adsl problems also affect the network speed, for a like a . For reference.
  • This information provided by the users.Thanks!