Autotuning dynamically changes the TCP Window Size - which often causes errors as loss of network connectivity, firewall problems, and so on.
To show the status of this autotuning, you should check it with admin rights under cmd with this command: netsh interface tcp show global
To disable use: netsh interface tcp set global autotuning=disabled
To reenable use: netsh interface tcp set global autotuning=normal
Another important thing concerning wireless problems - you should install Service Pack 2, as it does contain an bunch of hotfixes and other important stuff.