Hello there, im using windows 7 too. but im having problems changing the polling rate to 1000hz.
It works on windows vista with my mx518, but i can't change it on windows 7.
Ive done everything, how you said, but it won't work.
heres a pic of my desktop, which shows the drivers and that i changed them, but it just won't work. maybe something has changed in newer windows 7?