Right you have been having this trouble for ages now all i would do now is a major clean up.
MAKE SURE YOU BACK UP ANYTHING YOU WANT FROM YOU PC
1) Download your os (vista) and burn to a disc or make a bootable usb.
2) Completely wipe you HDD with Darik's Boot And Nuke this will erase everything on you HDD so we know there will be no viruses or maleware. Heres how to do it from a usb (
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3) Install your os (vista) from a usb or disc using your product code on side of your pc.
4) Hard reset your router (hold in little button for 20 seconds with pen or pin.
5) Just run your wireless adaptor and see how your game is if you still have trouble then its your internet or hardware in pc.