In regards to Acer W500--I had the Bluetooth and Rotation working on the Release Preview of Windows 8, but with the real version the drivers from Acer's website do not work. -For the Bluetooth: The Bluetooth driver is an executable that is incompatible with Windows 8 and I can't get device manager to find the bluetooth driver in the folder. -For the Rotation: The G-sensor driver, Device Control, and the Auto Screen Rotation Blocker from Acer install fine, but the screen will not rotate. -Also, some installation programs seem to be sluggish. Hopefully Microsoft or Acer will provide support for the W500 as it has a large consumer base. Anybody have any answers?

suggest you to download the G-Sensor and Bluetooth drivers for Windows 7 operating system from the manufacturer website and install it in Windows 7 compatibility mode and check if that help.
Refer this article if you are using Acer Iconia Tab W500.
Drivers & Downloads
http://us.acer.com/ac/en/US/content/drivers
Follow these steps to install the drivers in compatibility mode.
a. Download the drivers from the manufacturer’s website.
b. Right-click on the driver and click on properties.
c. Click on the ‘compatibility’ tab and check the box "Run this
program in compatibility mode for” and select Windows 7 operating system from the drop down. d. Click on ‘Apply’ and click ‘OK’ and run the file to install it.

Note: Since Windows 8 has just released yet not all drivers are going to work with it. Some drivers are very specific about the operating system version, so you might have to wait until the manufacturer releases Windows 8 drivers (if they make them for your model).
If the issue still persists, I would suggest you to contact Acer support for further assistance