Microsoft .net Framework 3.5 Windows Features Won't Turn On?

I am running Windows 7 Home Premium (SP1) on a fairly new machine.I ran malware and McAfee scans which were all clean. I also ran Aaron Stebner's .NET Framework setup verification tool (which was clean as well).I have been using a software program that uses "Microsoft .net 3.5".We have been having some issues with the program and were advised to turn on the following Windows features:Control Panel> Programs> Windows Features>Microsoft .Net 3.5>two checkmarks below thisI have repeatedly checked these, tow at a time, one at a time, etc and the system will give me a "wait message", state that all of the features could not be started and request a re-boot. Upon a re-boot, neither of these features are checked.I have also attempted to re-install 3.5 (and the program itself). We have been unable to re-install 3.5 (it appears to start but just disappears without any confirmation whatsoever).When I look in programs I have Microsoft.Net 4.0, which apparently is the "parent" of 3.5I have also entirely removed both McAfee & Malwarebytes thinking these may have been blocking us, all to no availby the way, system restore is also failing!