I use an application for commodities trading. I have to uninstall .Net framework 4.5.1 in order to run the trading software. Their tech support doesn't have any fixes. If you go to http://www.oaktrading.com/and click on Oak Desktop you'll be able to access their software. If you can get to their login screen it's working (you don't have to be logged in to determine if it works). I'm using Windows 7 and I've tried other versions of .Net framework without any luck.
This wasn't always the case. It first started in February of this year. Before then it worked fine. I may have been using 3.5 at that time - but the results are the same. I have to delete .Net Framework in order for it to work.