Microsoft Updates tried to download the latest .NET installment onto my Win7 32bit. It is a 5.5MB download. The download got to 50% then hung. So I ignored it eventually, as you do. But later that evening I couldn't boot down, Windows was still trying to download dot NET. 3 hours later my computer was still telling me not to power off because it was updating. Eventually I had to manually turn off the computer, something I only resort to as a last option. On booting up the next day I found that no restart could be attempted without triggering the dot NET download, which hangs the computer because it cannot download. I tried several fixes. Eventually the entire computer froze and would only function in Safe Mode. I removed the dot NET programme then reinstalled it again plus a System Restore. After 3 days of hell my computer started working normally again, but there is no guarantee that dot NET won't descend on me again. This is a real problem, there is a Microsoft page devoted to dot NET fixing which is hideously complicated to follow, but by posting it they have admitted that there is a problem.
I am posting this to alert others - if dot NET does its thing on you the first reaction is likely to be that you have a PUP or something, but it's a legitimate Microsoft download which can upset your computer - I almost lost my computer - without expert guidance you can wreck your entire system trying to sort out dot NET.