Have you tried Microsoft's solution?
Troubleshoot problems with installing updates
I want to update my Garmin GPS and It says I'm missing .NET Framework 4 Client Profile and to get the most updated verison I have to update my computer with Windows Update. My Windows Update hasn't work for along time and I've tried on and off to get it to work and nothing has helped. I've found someone who can fix it but they want over $150 to fix it... I've tried quite a few ideas on the forums and nothing is working. Can anyone help me?