If you have a windows CD (or an ISO) try doing an offline DISM install.
Launch an elevated command prompt by search for cmd. Right click the command prompt search result and click run as administrator.
Put in your windows DVD (or mount your ISO) and type the following exactly
This is assuming your DVD or ISO is listed as your D drive, if it is not, change the source letter. The spacing in this command looks weird but it is correct, make sure that you have it as it's listed here.
Dism.exe /online /enable-feature /featurename:NetFX3 /All /Source:D:\sources\sxs /LimitAccess
Edit - Oops, necro thread. Sorted by 0 replies. Can't delete. Sorry!