When I try to connect my Windows 8 laptop to the internet via internet tethering on my Lumia 920 either my laptop sees it, connects (is able to connect to the internet) but then loses the connection and can not see the phone, or it never sees the Lumia as a network. I have the most recent version of access point on my phone and the settings seem okay. My mobile package (O2 in the UK) includes tethering. It worked fine a few weeks ago but all of a sudden it stopped. Its the fact that my laptop can only sporadically see the phone that has got me curious, when it does everything works fine for a few minutes before it loses the connection. I have run the diagnostic wizard for the network adapter in windows but no luck.

Were there any changes (hardware or software) made to the computer prior to the issue?

Perform the steps mentioned below and see if it helps.

a: When the Connection is made, go to Network and Sharing center.
b: Then go to Manage Wireless Networks.
c: Select the connection (Lumia 920) right click on it and select properties.
d: Go to Security tab and then Advanced settings
e: Enable the Federal Information processing standard and save the setting.
f: Restart the computer.