Click Start, type Programs and Features in the Search box, and press Enter
Look down the list for "Microsoft .NET Framework ..." (or type Framework in the Search box at the upper right of the Programs and Features window) and see what version, if any, is installed.
If you need .NET Framework 4.0, go here:
Read at least the "System Requirements" and "Install Instructions." You probably should read "Details" as well. If you want the standalone installer (which is a large download) instead of the web installer, read the "Related Resources."
Also, this MS website may provide some help for you:
Hope above information can help you.
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