Check:

get-windowsfeature

if

NET-Framework-Core		-		removed

Insert Windows 8 DVD / server 2008 / server 2012

dism /online /enable-feature /featurename:NetFx3 /Source:E:\sources\sxs

dism /online /enable-feature /featurename:NetFx3 /All /LimitAccess /Source:"E:\sources\sxs"

2012

dism /online /enable-feature /featurename:NetFx3 /All /Source:E:\sources\sxs /LimitAccess  

Win 2008 R2 server

DISM /Online /Enable-Feature /FeatureName:NetFx3

.NET Framework 3.0 and 3.5 (installed together): NetFx3-ServerCore

If you need 32-bit support, run both of the following commands:

Dism /online /enable-feature /featurename:NetFx2-ServerCore-WOW64
Dism /online /enable-feature /featurename:NetFx3-ServerCore-WOW64

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