Solved Error when installing Framework 3.5

Some programs in which I need to use require NET Framework 3.5 installed. But the problem is that I can not install through panel "Windows Features" or the Command Prompt method where I saw in some tutorials.
I need help urgently!

i think you need to put the LimitAccess before the source to stop it looking on the internet,

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

i assume that F: is the correct drive of your install image/disc