I would first try using a wired connection to see if you can firmly place the blame on the wireless adapter.
If that is the case, then either remain with the wire or purchase another adapter that is Windows 7 compatible.
Another thing to try is the following procedure:
- download the Vista version of the driver
- uninstall the current version of the driver that's on the system by going to Control Panel...Programs...Uninstall a program.
- check in Device Manager to ensure that the device is uninstalled.
- Right click on the downloaded Vista driver and select "Properties", then select the Compatibility tab.
- Click on the button to "Change settings for all users"
- Then select the box to "Run as Windows Vista" and the box to "Run as administrator"
- Then click on OK to accept the changes.
- Then right click on the installer and select "Run as administrator" and let it install.