reset your router, (take the power out the back of it leave it out for 1 minute, plug it back in) (pressing the reset switch is not recommended as this resets alot of functions) if that doesnt work, hit the reset switch. download something from the microsoft website, anything just to see what speed comes up and cancel (microsoft will always have the fastest/most secure connection in the world) check what your speed is, come back and let us know the outcome.
(could also be your ISP server in your area is under alot of strain and people are downloading alot atm or that too many people are on the server at the moment)
If the problem persists, within the day- assuming you have a dynamic IP- the connection should change somewhat and reallocate you to another server if you cant wait, ring your ISP and tell them to reset your connection, then come back and tell us if this helped you out.
Also if that doesnt work go to command prompt start>all programs> accessories >right click command prompt, run as administrator, press enter for UAC type in cd\
then type ipconfig flushdns
comeback and let me know everything