Solutions from http://www.istikonline.com/
==========
SOLUTION (Step 1):
- Insert your Huawei E220 into a PC not running Windows Vista,
- Copy all files and folder from your Huawei E220 to a flash drive.
- Insert this flash drive to Vista PC and open it. Click Autorun.exe and let it install.
- Restart PC, then insert your Huawei E220, and Vista should start to install the drivers required by the device. If still not work, continue with Step 2.
SOLUTION (Step 2):
- After Step 1 restart, insert your Huawei E220 to the same USB port.
- Run Device Manager, let scan for hardware changes.
- under Universal Serial Bus controllers, you will notice that a USB Mass Storage device with a "!" mark, indicating that it has a conflict.
- Right click on it and Uninstall.
- Now let Device Manager scan again for hardware change and for sure it will now detect your Huawei 3G Modem!!