If someone has problems installing the official Motorola adb and fastboot drivers for Windows, try the following, this works for me:

1. download the UniversalADB driver from @Koush here: https://github.com/koush/UniversalAdbDriver
2. install it
3. locate the file android_winusb.inf in the folder (may vary) x:\Program Files\ClockworkMod\Universal Adb Driver\usb_driver
4. open it with any texteditor
5. add the following two lines (somewhere in the devices section) and save the file:
   Code:

MotorolaADBInterface = USB_Install, USB\VID_22B8&PID_2E76&REV_0228&MI_01
MotorolaBootLoaderInterface = USB_Install, USB\VID_22B8&PID_2E80&REV_0100

6. let Windows install this driver from koush's directory once in adb mode and once in fastboot mode (two drivers!)
7. enjoy!