To install dotnet framework 3.5 you’ll will have to do a couple of things. First of all you need to disable a task as soons as you have completed setup. Well this is actually optional. It is necessary to do this step if you want to deploy that image to other PC’s. Windows 8(.1) deletes install media to save disk space. Run the following command immediately after setup completed:

schtasks.exe /change /disable /tn "\Microsoft\Windows\AppxDeploymentclient\Pre-Staged App CleanUp"

To install the DotNet Framework 3.5 feature in Windows 8(.1) run the following command. Where D: is the installtion media

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs

All of the above of course in an elevated Powershell window