need to register with the Windows Insider program to get updates. http://insider.windows.com
may also need a registry fix, as suggested.  there is a windows update that can reset the 'flighting' settings (preview build settings): http://answers.microsoft.com/en-us/insider/forum/insider_wintp-insider_update/windows-update-does-not-find-build-10041/7223f419-a468-45ce-9ba5-fdcee1317c92?page=1&tm=1426777875899

re updates, right now (subject to change):
If you choose 'fast' track, you'll end up on 10049
If you choose 'slow' track, you'll end up on 10041


saved wifi passwords - I have onedrive syncing these between my windows phone and all my windows pc's. never have to re-enter them again :-)