As in the mouse just won't work *period*, or the drivers won't work but the mouse still manages fine? Make sure you have the right set of drivers -- there's one for the Diamondback and one for the 3G and they aren't compatible with one another.
Double check to see if the mouse is showing up in Device Manager. It'll probably be listed as a HID device if no drivers are installed (along with a HID device for every other USB mouse/keyboard/joystick you have plugged in at the time). You can also check under Devices and Printers (I think that's what it's called) to see if it's listed. If it's not listed in device manager -- ie: you can't trace a HID device down to the mouse -- then the system isn't even seeing it plugged in. That might be indicitive of a more serious problem. If it does see it as a HID device but it's not working, then it's some residual driver or something left over.
In either case, try plugging it into different USB ports and directly to the motherboard if you're going off a hub or a USB port on the case.
If the mouse is totally kaput on that system, you can try to reflash the firmware on another system (maybe even your current). And to rule out residual software entries, you can search the registry for Razer entries and remove them. That should get rid of residual stuff in Device Manager, too. Might wanna export your entire registry and create a system restore point before you go deleting, just in case something goes AWOL.
Barring the above, contact Razer tech support. They were pretty good the one time I contacted them.
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