I tried to install Live Essentials 2012 on Windows 8 and it required .NET 3.5. I tried to install it (both download and from Programs and Features) and the installer tried to download the code. The download would fail with a 0x800F0906 error:
Windows couldn’t connect to the Internet to download necessary files. Make sure that you’re connected to the Internet, and click Retry to try again.
Some googling ensued and I found a fix. Pop in the installation media for Windows 8 and run DISM from an elevated (admin) command prompt. E:\ was the path to my Windows 8 installation USB.
Not exactly user friendly! The Live Essentials 2012 install worked fine after that.
It appears that this is caused by the machine being policy configured to use WSUS or similar with the download of .NET 3.5 not being available.