I have also previously had issues with WiFi - this is not usually the wifi implementation in the Qtek 8310 but rather the out-of-spec wireless router or access point you might be running.
Most routers I have tried with the following:
- WPA2 encryption
- Turbo/105Mbps/125Mbps/54g+ or any other speed increasing technology
- *Some* 54g routers with no mixed/mode wifi implementation - 'g only'
Do not function correctly with the Qtek 8310 wireless. I believe the further from the basic 11b spec routers get the harder the qtek finds it to connect - I have had great success with linksys routers (without turbo mode) and Zyxel equipment (they let you explicitly enable functions such as mixed mode wireless).
Your mileage may vary with your router/ap but its worth advising upgrading to the latest firmware (only do this if you are comfortable and no what it entails) and then playing with the channels and settings to see what results you get.
First thing to try though - try disabling that 'turbo' mode!