Does anybody know the easiest way to get 500hz in vista x64 and a mx518??

Please help, this is driving me insane. THANKS!!

vista x64 only allows the use of signed drivers.
you need to either

sign the driver that allows 500hz
or

disable the requirement for signed drivers (can be done by pressing f8 every time you reboot) and use a patched usbport.sys.

There are some guides on the internet how to sign drivers. I'll see if i find one later.

http://sweetlow.at.tut.by/download/hidusbf.zip

I've used that program to adjust the USB rate on Vista x64. The readme file contains a link to a guide where it tells you how to sign the driver.